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Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2012	Oct. 29, 2012
Entity Information [Line Items]
Entity Registrant Name	WESCO INTERNATIONAL INC.
Entity Central Index Key	0000929008
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2012
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding (in shares)		43,746,966

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2012	Dec. 31, 2011
Current Assets:
Cash and cash equivalents	$ 107,637	$ 63,869
Trade accounts receivable, net of allowance for doubtful accounts of $20,811 and $21,590 in 2012 and 2011, respectively	1,020,454	939,422
Other accounts receivable	48,246	43,442
Inventories, net	662,764	626,967
Current deferred income taxes	29,431	28,217
Income taxes receivable	11,284	12,206
Prepaid expenses and other current assets	26,109	23,297
Total current assets	1,905,925	1,737,420
Property, buildings and equipment, net of accumulated depreciation of $189,971 and $190,385 in 2012 and 2011, respectively	140,998	133,550
Intangible assets, net	204,572	156,874
Goodwill	1,127,001	1,008,127
Deferred income taxes	17,926	18,090
Other assets	23,572	24,391
Total assets	3,419,994	3,078,452
Current Liabilities:
Accounts payable	693,177	642,777
Accrued payroll and benefit costs	63,103	76,915
Short-term debt	22,848	3,261
Current portion of long-term debt	2,137	3,150
Bank overdrafts	57,681	47,489
Other current liabilities	71,090	72,254
Total current liabilities	910,036	845,846
Long-term debt, net of discount of $174,485 and $175,908 in 2012 and 2011, respectively	696,758	642,922
Deferred income taxes	244,175	223,005
Other noncurrent liabilities	24,495	20,769
Total liabilities	1,875,464	1,732,542
Stockholders' Equity:
Preferred stock, $.01 par value; 20,000,000 shares authorized, no shares issued or outstanding	0	0
Additional capital	1,053,493	1,036,867
Retained earnings	1,066,216	891,789
Treasury stock, at cost; 18,023,348 and 17,936,923 shares in 2012 and 2011, respectively	(600,059)	(593,329)
Accumulated other comprehensive income	24,354	10,057
Total WESCO International stockholders' equity	1,544,622	1,345,998
Noncontrolling interest	(92)	(88)
Total stockholders' equity	1,544,530	1,345,910
Total liabilities and stockholders' equity	3,419,994	3,078,452
Common Stock [Member]
Stockholders' Equity:
Common stock	575	571
Common Class B [Member]
Stockholders' Equity:
Common stock	$ 43	$ 43

CONSOLIDATED BALANCE SHEETS PARENTHETICAL (Parentheticals) - USD ($) $ in Thousands	Sep. 30, 2012	Dec. 31, 2011
Allowance for doubtful accounts	$ 20,496	$ 21,590
Accumulated depreciation	195	190
Debt discount	$ 173,685	$ 175,908
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	20,000,000	20,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Treasury stock, shares (in shares)	18,042,118	17,936,923
Common Stock [Member]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	210,000,000	210,000,000
Common stock, shares issued (in shares)	57,420,260	57,021,523
Common stock, shares outstanding (in shares)	43,717,573	43,424,031
Common Class B [Member]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	20,000,000	20,000,000
Common stock, shares issued (in shares)	4,339,431	4,339,431
Common stock, shares outstanding (in shares)	0	0

CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	Sep. 30, 2012	Jun. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Net sales	$ 1,656,186	$ 1,580,376	$ 4,934,938	$ 4,536,196
Cost of goods sold	1,317,432	1,264,745	3,940,762	3,627,666
Selling, general and administrative expense	225,812	216,205	685,130	644,176
Depreciation and amortization	9,910	7,674	26,431	22,861
Income from operations	103,032	91,752	282,615	241,493
Interest expense, net	12,654	15,079	33,093	41,651
Income before income taxes	90,378	76,673	249,522	199,842
Provision for income taxes	26,987	22,783	74,259	58,440
Net income	63,391	53,890	175,263	141,402
Net income attributable to noncontrolling interest	(24)	0	(4)	0
Net income attributable to WESCO International, Inc.	63,415	53,890	175,267	141,402
Comprehensive Income:
Foreign currency translation adjustment	10,652	(26,411)	14,297	(16,685)
Comprehensive income attributable to WESCO International, Inc.	$ 74,067	$ 27,479	$ 189,564	$ 124,717
Earnings per share attributable to WESCO International, Inc.
Basic (in dollars per share)	$ 1.45	$ 1.24	$ 4.02	$ 3.27
Diluted (in dollars per share)	$ 1.25	$ 1.11	$ 3.43	$ 2.84

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Operating Activities:
Net income	$ 175,263	$ 141,402
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	26,431	22,861
Amortization of debt issuance costs	1,898	3,838
Amortization of debt discount	2,208	1,850
Deferred income taxes	21,934	7,702
Stock-based compensation expense	11,722	12,360
Loss on sale of property, buildings and equipment	439	171
Excess tax benefit from stock-based compensation	(5,560)	(3,523)
Interest related to uncertain tax positions	(3,288)	1,581
Changes in assets and liabilities
Trade and other receivables, net	(64,017)	(154,686)
Inventories, net	(16,028)	(44,155)
Prepaid expenses and other current assets	9,129	(998)
Accounts payable	38,540	110,550
Accrued payroll and benefit costs	(15,403)	(2,686)
Other current and noncurrent liabilities	6,415	(24,439)
Net cash provided by operating activities	189,683	71,828
Investing Activities:
Capital expenditures	(19,469)	(23,966)
Acquisition payments, net of cash acquired	(201,123)	(8,166)
Proceeds from sale of assets	51	86
Net cash used in investing activities	(220,541)	(32,046)
Financing Activities:
Proceeds from issuance of short-term debt	21,388	0
Repayments of short-term debt	(2,129)	0
Proceeds from issuance of long-term debt	740,450	464,981
Repayments of long-term debt	(691,202)	(464,900)
Debt issuance costs	(137)	(4,248)
Proceeds from the exercise of stock options	208	210
Excess tax benefit from stock-based compensation	5,560	3,523
Repurchase of common stock	(8,237)	(6,250)
(Decrease) increase in bank overdrafts	10,192	12,999
Payments on capital lease obligations	(1,702)	(1,110)
Net cash (used in) provided by financing activities	74,391	5,205
Effect of exchange rate on cash and cash equivalents	235	(4,515)
Net change in cash and cash equivalents	43,768	40,472
Cash and cash equivalents at the beginning of the period	63,869	53,577
Cash and cash equivalents at the end of the period	107,637
Non-cash investing and financing activities:
Property, buildings and equipment acquired through capital leases	2,693	210
Issuance of treasury stock	$ 0	$ 960

ORGANIZATION	9 Months Ended
ORGANIZATION	Sep. 30, 2012
Organization, Consolidation and Presentation of Financial Statements [Abstract]
ORGANIZATION	ORGANIZATION WESCO International, Inc. and its subsidiaries (collectively, “WESCO”), headquartered in Pittsburgh, Pennsylvania, is a full-line distributor of electrical, industrial and communications maintenance, repair and operating (“MRO”) and original equipment manufactures (“OEM”) products, construction materials, and advanced supply chain management and logistics services used primarily in the industrial, construction, utility and commercial, institutional and government markets. We serve over 65,000 active customers globally, through approximately 400 full service branches and eight distribution centers located primarily in the United States, Canada and Mexico, with offices in 11 additional countries.

ACCOUNTING POLICIES	9 Months Ended
ACCOUNTING POLICIES	Sep. 30, 2012
Accounting Policies [Abstract]
ACCOUNTING POLICIES	ACCOUNTING POLICIES Basis of Presentation The unaudited condensed consolidated financial statements of WESCO have been prepared in accordance with Rule 10-01 of Regulation S-X of the Securities and Exchange Commission (the “SEC”). The unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in WESCO’s 2011 Annual Report on Form 10-K filed with the SEC. The December 31, 2011 condensed consolidated balance sheet data was derived from audited financial statements but does not include all disclosures required by accounting principles generally accepted in the United States. The unaudited condensed consolidated balance sheet as of September 30, 2012, the unaudited condensed consolidated statements of income for the three and nine months ended September 30, 2012 and 2011, respectively, and the unaudited condensed consolidated statements of cash flows for the nine months ended September 30, 2012 and 2011, respectively, in the opinion of management, have been prepared on the same basis as the audited consolidated financial statements and include all adjustments necessary for the fair statement of the results of the interim periods. All adjustments reflected in the unaudited condensed consolidated financial statements are of a normal recurring nature unless indicated. Results for the interim periods presented are not necessarily indicative of the results to be expected for the full year. Reclassification Certain prior period amounts have been reclassified to conform with the current period's financial statement presentation. Fair Value of Financial Instruments The Company measures the fair value of financial assets and liabilities based on the guidance of ASC 820, "Fair Value Measurements and Disclosures," which defines fair value, establishes a framework for measuring fair value, and expands disclosures about fair value measurements. ASC 820 establishes a fair value hierarchy, which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. ASC 820 describes three levels of inputs that may be used to measure fair value: Level 1 inputs are quoted prices in active markets for identical assets or liabilities. Level 2 inputs include inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices in active markets for similar assets and liabilities, quoted prices for identical or similar assets or liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of assets or liabilities. Level 3 inputs are unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions. At September 30, 2012, the carrying value of WESCO’s 7.50% Senior Subordinated Notes due 2017 (the "2017 Notes") and 6.0% Convertible Senior Debentures due 2029 (the "2029 Debentures") was $494.9 million and the fair value was approximately $892.9 million. At December 31, 2011, the carrying value of WESCO’s 2017 Notes and 2029 Debentures was $495.0 million and the fair value was approximately $850.9 million. The fair value of WESCO’s 2017 Notes and 2029 Debentures is based on quoted prices in active markets and is therefore classified as Level 1 within the valuation hierarchy. The reported carrying amounts of WESCO’s other debt instruments approximate their fair values and are classified as Level 2 within the valuation hierarchy. Other debt instruments included in Level 2 are valued using a market approach, utilizing interest rates and other relevant information generated by market transactions involving similar instruments. Recent Accounting Pronouncements In July 2012, the Financial Accounting Standards Board (the "FASB"), issued updated guidance on the periodic testing of indefinite-lived intangible assets, other than goodwill, for impairment. This updated guidance will allow companies the option to first assess qualitative factors to determine if it is more-likely-than-not that an indefinite-lived intangible asset might be impaired and whether it is necessary to perform the quantitative impairment test required under current accounting standards. This guidance is effective for annual and interim impairment tests performed for fiscal years beginning after September 15, 2012. WESCO will adopt this guidance in 2013. Adoption of this guidance is not expected to have a material impact on WESCO's financial position, results of operations or cash flows.

ACQUISITIONS

9 Months Ended

Sep. 30, 2012

Business Combinations [Abstract]

ACQUISITIONS

The following table sets forth the consideration paid for acquisitions:



Nine Months Ended September 30	2012			2011
(In thousands)
Details of acquisitions:
Fair value of assets acquired	$	215,303		$	11,187
Fair value of liabilities assumed	(14,180		)	(3,021		)
Cash paid for acquisitions	$	201,123		$	8,166

2011 Acquisition of RECO, LLC

On March 14, 2011, WESCO Distribution, Inc. ("WESCO Distribution") completed its acquisition of RECO, LLC ("RECO"), an automation, controls, and electrical distributor located in the midwest and southeastern regions of the United States with approximately $25 million in annual sales. WESCO funded the purchase price paid at closing with cash and borrowings under the Receivables Facility. The purchase price was allocated to the respective assets and liabilities based upon their estimated fair values as of the acquisition date. The excess of the purchase price over the fair value of the net assets acquired has been allocated to goodwill valued at $6.0 million. Management believes the majority of goodwill will be deductible for tax purposes.

2012 Acquisitions of RS Electronics, Trydor Industries (Canada), Ltd., and Conney Safety Products, LLC

On January 3, 2012, WESCO Distribution, Inc. completed its acquisition of RS Electronics, a leading North American distributor of electronic and electrical products serving primarily the industrial, medical equipment, automotive, and contract manufacturing end markets with eight branches located in the midwest and southeastern United States and approximately $60 million in annual sales. WESCO funded the purchase price paid at closing with cash and borrowings under the Receivables Facility.

On July 5, 2012, WESCO completed its acquisition of Trydor Industries (Canada), Ltd. (“Trydor”) through one of its wholly-owned Canadian subsidiaries. Trydor Industries (Canada), Ltd. is a full-line distributor of high-voltage electrical products and services addressing the transmission, substation and distribution network needs for utilities, independent power producers and utility contractors in Canada with approximately $35 million in annual sales. WESCO funded the purchase price paid at closing with borrowings under the Revolving Credit Facility.

On July 10, 2012, WESCO Distribution completed its acquisition of Conney Safety Products, LLC (“Conney Safety”), a premier distributor of MRO safety products with approximately $85 million in annual sales. WESCO funded the purchase price paid at closing with borrowings under the Receivables Facility.

For all 2012 acquisitions, the purchase price was allocated to the respective assets and liabilities based upon their estimated fair values as of the acquisition date. The purchase price allocation of RS Electronics was finalized in the first quarter of 2012. The purchase price allocation of Conney Safety and Trydor will be finalized during the fourth quarter of 2012. The excess of the purchase price over the fair value of the net assets acquired, including intangible assets, has been allocated to goodwill. The fair value of intangible assets was estimated by management and the allocation resulted in goodwill and intangible assets of $114.9 million and $57.0 million, respectively. Management believes the majority of goodwill will be deductible for tax purposes. The intangible assets for all 2012 acquisitions include customer relationships of $49.2 million amortized over 10 to 12 years, supplier relationships of $2.7 million amortized over 10 years and trademarks of $5.1 million. Certain trademarks have been assigned an indefinite life while others are being amortized over 4 to 15 years. No residual value is estimated for the intangible assets.

- Definition

The entire disclosure for a business combination (or series of individually immaterial business combinations) completed during the period, including background, timing, and recognized assets and liabilities. The disclosure may include leverage buyout transactions (as applicable).

+ References

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-Name Emerging Issues Task Force (EITF)
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+ Details

STOCK-BASED COMPENSATION

9 Months Ended

Sep. 30, 2012

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

STOCK-BASED COMPENSATION

WESCO’s stock-based employee compensation plans are comprised of stock options, stock-settled stock appreciation rights, restricted stock units and performance-based awards. Compensation cost for all stock-based awards is measured at fair value on the date of grant, and compensation cost is recognized, net of estimated forfeitures, over the service period for awards expected to vest. The fair value of stock options and stock-settled appreciation rights is determined using the Black-Scholes valuation model. The fair value of restricted stock units is determined by the grant-date closing price of WESCO’s common stock. The forfeiture assumption is based on WESCO’s historical employee behavior that is reviewed on an annual basis. No dividends are assumed.

During the three and nine month periods ended September 30, 2012 and 2011, WESCO granted the following stock-settled stock appreciation rights, restricted stock units and performance-based awards at the following weighted average assumptions:



	Three Months Ended September 30,				Nine Months Ended September 30,
	2012		2011		2012		2011
Stock-settled appreciation rights granted	850		15,156		257,932		399,330
Restricted stock units granted	2,400		—		74,724		53,852
Performance-based awards granted	—		—		46,804		—
Risk free interest rate	0.6	%	1.0	%	0.9	%	2.3	%
Expected life (in years)	5.0		5.0		5.0		5.0
Expected volatility	50	%	48	%	50	%	49	%

For the three and nine months ended September 30, 2012, the weighted average fair value per stock-settled appreciation right granted was $24.33 and $27.89, respectively. For the three and nine months ended September 30, 2011, the weighted average fair value per stock-settled appreciation right granted was $16.42 and $26.47, respectively. For the three and nine months ended September 30, 2012, the weighted average fair value per restricted stock unit granted was $62.49 and $64.27, respectively. For the nine months ended September 30, 2011, the weighted average fair value per restricted stock unit granted was $60.05. For the nine months ended September 30, 2012, the weighted average fair value per performance-based award granted was $75.72.

The following table sets forth a summary of stock options and stock-settled stock appreciation rights and related information for the nine months ended September 30, 2012:



	Awards		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (In Years)	Aggregate Intrinsic Value (In thousands)
Outstanding at December 31, 2011	4,266,533		$	39.64
Granted	257,932		64.12
Exercised	(697,037	)	32.46
Forfeited	(36,061	)	49.43
Outstanding at September 30, 2012	3,791,367		42.54		5.8	$	72,535
Exercisable at September 30, 2012	3,084,703		$	40.06	5.1	$	66,470

The following table sets forth a summary of restricted stock units and related information for the nine months ended September 30, 2012:



	Awards		Weighted Average Fair Value
Unvested at December 31, 2011	203,291		$	37.16
Granted	74,724		64.27
Vested	(78,305	)	25.37
Forfeited	(8,684	)	45.02
Unvested at September 30, 2012	191,026		$	52.24

Performance shares are awards for which the vesting will occur based on market or performance conditions. The following table sets forth a summary of performance-based awards for the nine months ended September 30, 2012:



	Awards		Weighted Average Fair Value
Unvested at December 31, 2011	—		—
Granted	46,804		$	75.72
Vested	—		—
Forfeited	(304	)	75.72
Unvested at June 30, 2012	46,500		$	75.72

The performance-based awards in the table above include 23,250 shares in which vesting of the ultimate number of shares underlying such awards will be dependent upon WESCO's total stockholder return in relation to the total stockholder return of a select group of peer companies over a three-year period. These awards are valued based upon a Monte Carlo simulation model, which is a valuation model that represents the characteristics of these grants. The probability of meeting the market criteria was considered when calculating the estimated fair market value on the date of grant. These awards were accounted for as awards with market conditions, which are recognized over the service period, regardless of whether the market conditions are achieved and the awards ultimately vest.

The fair value of the performance shares granted during the nine months ended September 30, 2012 were estimated using the following weighted-average assumptions:



Weighted Average Assumptions
Grant date share price	$	64.33
WESCO expected volatility	41.97		%
Peer group median volatility	33.40		%
Risk-free interest rate	0.40		%
Correlation	135.4		%

Vesting of the remaining 23,250 shares of performance-based awards in the table above will be dependent upon the three-year average growth rate of WESCO's net income. These awards are valued based upon the grant-date closing price of WESCO's common stock. These awards were accounted for as awards with performance conditions, in which stock-based compensation expense is recognized over the performance period based upon WESCO's determination of whether it is probable that the performance targets will be achieved.

WESCO recognized $3.2 million and $2.9 million of non-cash stock-based compensation expense, which is included in selling, general and administrative expenses, for the three months ended September 30, 2012 and 2011, respectively. WESCO recognized $11.7 million and $12.4 million of non-cash stock-based compensation expense, which is included in selling, general and administrative expenses, for the nine months ended September 30, 2012 and 2011, respectively. As of September 30, 2012, there was $21.4 million of total unrecognized compensation cost related to non-vested stock-based compensation arrangements for all awards previously made, of which approximately $3.4 million is expected to be recognized over the remainder of 2012, $11.4 million in 2013, $5.9 million in 2014 and $0.7 million in 2015.

During the nine months ended September 30, 2012 and 2011, the total intrinsic value of awards exercised was $22.4 million and $12.0 million, respectively. The total amount of cash received from the exercise of options was $0.2 million for both the nine months ended September 30, 2012 and 2011. The tax benefit associated with the exercise of awards for the nine months ended September 30, 2012 and 2011 totaled $5.4 million and $3.5 million, respectively, and was recorded as an increase to additional capital.

- Definition

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph 64, 65, A240
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Statement of Position (SOP)
-Number 93-6
-Paragraph 53
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 14

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 50
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6406099&loc=d3e25284-112666

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-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
-Paragraph 1
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-Paragraph 2
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-Name Accounting Standards Codification
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-Name Accounting Standards Codification
-Topic 718
-SubTopic 40
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6418621&loc=d3e17540-113929

+ Details

EARNINGS PER SHARE

9 Months Ended

Sep. 30, 2012

Earnings Per Share [Abstract]

EARNINGS PER SHARE

Basic earnings per share are computed by dividing net income by the weighted average common shares outstanding during the periods. Diluted earnings per share are computed by dividing net income by the weighted average common shares and common share equivalents outstanding during the periods. The dilutive effect of common share equivalents is considered in the diluted earnings per share computation using the treasury stock method, which includes consideration of stock-based compensation and convertible debt.

The following table sets forth the details of basic and diluted earnings per share:



	Three Months Ended
	September 30,
	2012		2011
Net income attributable to WESCO International, Inc.	$	63,415	$	53,890
Weighted average common shares outstanding used in computing basic earnings per share	43,705		43,289
Common shares issuable upon exercise of dilutive equity awards	1,032		976
Common shares issuable from contingently convertible debentures (see below for basis of calculation)	6,036		4,206
Weighted average common shares outstanding and common share equivalents used in computing diluted earnings per share	50,773		48,471
Earnings per share attributable to WESCO International, Inc.
Basic	$	1.45	$	1.24
Diluted	$	1.25	$	1.11



	Nine Months Ended
	September 30,
	2012		2011
Net income attributable to WESCO International, Inc.	$	175,267	$	141,402
Weighted average common shares outstanding used in computing basic earnings per share	43,596		43,181
Common shares issuable upon exercise of dilutive equity awards	1,199		1,202
Common shares issuable from contingently convertible debentures (see below for basis of calculation)	6,262		5,400
Weighted average common shares outstanding and common share equivalents used in computing diluted earnings per share	51,057		49,783
Earnings per share attributable to WESCO International, Inc.
Basic	$	4.02	$	3.27
Diluted	$	3.43	$	2.84

For the three and nine months ended September 30, 2012, the computation of diluted earnings per share attributable to WESCO International, Inc. excluded 1.0 million and 1.2 million, respectively, of stock-settled stock appreciation rights at weighted average exercise prices of $64 per share and $62 per share, respectively. These amounts were excluded because their effect would have been antidilutive.

Because of WESCO’s obligation to settle the par value of the 6.0% Convertible Senior Debentures due 2029 (the “2029 Debentures”) and the previously outstanding 1.75% Convertible Senior Debentures due 2026 (the “2026 Debentures” and together with the 2029 Debentures, the “Debentures”) in cash upon conversion, WESCO is not required to include any shares underlying the Debentures in its diluted weighted average shares outstanding until the average stock price per share for the period exceeds the conversion price of the respective Debentures. At such time, only the number of shares that would be issuable (under the treasury stock method of accounting for share dilution) would be included, which is based upon the amount by which the average stock price exceeds the conversion price. The conversion price of the 2029 Debentures is $28.87. Share dilution is limited to a maximum of 11,949,513 shares for the 2029 Debentures. For the three and nine months ended September 30, 2012, the effect of the Debentures on diluted earnings per share attributable to WESCO International, Inc. was a decrease of $0.17 and $0.48, respectively. For the three and nine months ended September 30, 2011, the effect of the Debentures on diluted earnings per share attributable to WESCO International, Inc. was a decrease of $0.11 and $0.35, respectively.

EMPLOYEE BENEFIT PLANS	9 Months Ended
EMPLOYEE BENEFIT PLANS	Sep. 30, 2012
Compensation and Retirement Disclosure [Abstract]
EMPLOYEE BENEFIT PLANS	EMPLOYEE BENEFIT PLANS A majority of WESCO’s employees are covered by defined contribution retirement savings plans for their services rendered subsequent to WESCO’s formation. WESCO also offers a deferred compensation plan for select individuals. For U.S. participants, WESCO will make contributions in an amount equal to 50% of the participant’s total monthly contributions up to a maximum of 6% of eligible compensation. For Canadian participants, WESCO will make contributions in an amount ranging from 1% to 7% of the participant’s eligible compensation based on years of continuous service. In addition, employer contributions may be made at the discretion of the Board of Directors. For the nine months ended September 30, 2012 and 2011, WESCO incurred charges of $24.2 million and $19.5 million, respectively, for all such plans. Contributions are made in cash to defined contribution retirement savings plans. The deferred compensation plan is an unfunded plan. Employees have the option to transfer balances allocated to their accounts into any of the available investment options, including WESCO common stock.

- Definition

The entire disclosure for pension and other postretirement benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph a
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph b
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
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-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 106
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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 87
-Paragraph 264
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
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-Number 03-2
-Paragraph 8
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 30
-Paragraph 26
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 10: http://www.xbrl.org/2003/role/presentationRef
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-Name FASB Staff Position (FSP)
-Number FAS106-2
-Paragraph 20, 21, 22
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 158
-Paragraph 7, 21, 22
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5, 6, 7, 8
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Implementation Guide (Q and A)
-Number FAS88
-Paragraph 63
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/topic&trid=2235017

+ Details

COMMITMENTS AND CONTINGENCIES	9 Months Ended
COMMITMENTS AND CONTINGENCIES	Sep. 30, 2012
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES WESCO is a co-defendant in a lawsuit filed in a state court in Indiana in which a customer alleges that WESCO sold defective products manufactured or remanufactured by others and is seeking monetary damages in the amount of approximately $50 million. WESCO has denied any liability, continues to believe that it has meritorious defenses and intends to vigorously defend itself against these allegations. Accordingly, no liability was recorded for this matter as of September 30, 2012. Furthermore, due to the uncertainty of this litigation, WESCO is not currently able to reasonably estimate the possible loss or range of loss from this legal proceeding.

- Definition

The entire disclosure for commitments and contingencies.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 14
-Paragraph 3
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
-Paragraph 9, 10, 11, 12
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.25)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
-Paragraph 4
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Reference 5: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12565-110249

Reference 6: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6449706&loc=d3e16207-108621

+ Details

INCOME TAXES	9 Months Ended
INCOME TAXES	Sep. 30, 2012
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES The effective tax rate for the three months ended September 30, 2012 and 2011 was 29.9% and 29.7% respectively, and the effective tax rate for the nine months ended September 30, 2012 and 2011 was 29.8% and 29.2%, respectively. WESCO’s three and nine month effective tax rates are lower than the federal statutory rate of 35% primarily due to benefits resulting from the recapitalization of Canadian operations, which are partially offset by nondeductible expenses, state taxes and foreign rate differences. The effective tax rate for the nine months ended September 30, 2012 and 2011 reflects beneficial discrete adjustments totaling $3.2 million and $2.1 million, respectively, primarily related to state taxes and changes in uncertain tax positions. The beneficial discrete adjustments in the effective tax rate for the three months ended September 30, 2012 and 2011 were immaterial. The total amount of net unrecognized tax benefits were $20.1 million and $20.9 million as of September 30, 2012 and December 31, 2011, respectively. A related deferred tax asset in the amount of $23.1 million excluding interest was recorded in 2011. If these tax benefits were recognized in the consolidated financial statements, the portion of these amounts that would reduce WESCO’s effective tax rate would be $20.2 million and $19.7 million, respectively. This amount would be offset by a decrease in the corresponding deferred tax asset discussed above. During the next twelve months, it is reasonably possible that the amount of unrecognized tax benefits will decrease by as much as $15.5 million (all of which will be offset by the reversal of a deferred tax asset) due to possible resolution of federal, state and/or foreign tax examinations and/or the expiration of statutes of limitations. Management does not expect this decrease to have an impact on the effective tax rate. WESCO records interest related to uncertain tax positions as a part of interest expense in the consolidated statement of income. Penalties are recognized as part of income tax expense. As of September 30, 2012 and December 31, 2011, WESCO had an accrued liability for interest related to uncertain tax positions of $8.1 million and $11.4 million, respectively. During the nine months ended September 30, 2012, accrued interest and net interest expense decreased by $3.3 million primarily as a result of a favorable Internal Revenue Service appeals settlement in the first quarter of 2012 related to the years 2000 to 2006. There were no material penalties recorded during the three or nine months ended September 30, 2012 or 2011.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Paragraph h
-Article 4

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 109
-Paragraph 136, 172
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 109
-Paragraph 43, 44, 45, 46, 47, 48, 49
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319

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-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32639-109319

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(h))
-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

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-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32559-109319

+ Details

OTHER FINANCIAL INFORMATION

9 Months Ended

Sep. 30, 2012

Condensed Financial Information [Abstract]

OTHER FINANCIAL INFORMATION

WESCO Distribution, a 100% owned subsidiary of WESCO International, Inc. ("WESCO International"), has outstanding $150.0 million in aggregate principal amount of 7.50% Senior Subordinated Notes due 2017 (the "2017 Notes"), and WESCO International has outstanding $344.9 million in aggregate principal amount of 2029 Debentures. The 2017 Notes are fully and unconditionally guaranteed by WESCO International on a subordinated basis to all existing and future senior indebtedness of WESCO International. The 2029 Debentures are fully and unconditionally guaranteed by WESCO Distribution on a senior subordinated basis to all existing and future senior indebtedness of WESCO Distribution.

Condensed consolidating financial information for WESCO International, WESCO Distribution and the non-guarantor subsidiaries is as follows:

WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATING BALANCE SHEETS

(unaudited)



	September 30, 2012
	(In thousands)
	WESCO International, Inc.		WESCO Distribution, Inc.		Non-Guarantor Subsidiaries		Consolidating and Eliminating Entries			Consolidated
Cash and cash equivalents	$	3	$	75,673	$	31,961	$	—		$	107,637
Trade accounts receivable, net	—		—		1,020,454		—			1,020,454
Inventories, net	—		337,316		325,448		—			662,764
Other current assets	—		38,423		76,647		—			115,070
Total current assets	3		451,412		1,454,510		—			1,905,925
Intercompany receivables, net	—		—		1,751,125		(1,751,125		)	—
Property, buildings and equipment, net	—		59,543		81,455		—			140,998
Intangible assets, net	—		6,360		198,212		—			204,572
Goodwill and other intangibles, net	—		246,125		880,876		—			1,127,001
Investments in affiliates and other noncurrent assets	2,426,032		3,601,264		30,989		(6,016,787		)	41,498
Total assets	$	2,426,035	$	4,364,704	$	4,397,167	$	(7,767,912	)	$	3,419,994
Accounts payable	$	—	$	444,291	$	248,886	$	—		$	693,177
Other current liabilities	2,578		57,161		157,120		—			216,859
Total current liabilities	2,578		501,452		406,006		—			910,036
Intercompany payables, net	679,405		1,071,720		—		(1,751,125		)	—
Long-term debt	171,244		187,988		337,526		—			696,758
Other noncurrent liabilities	28,126		182,443		58,101		—			268,670
Stockholders’ equity	1,544,682		2,421,101		3,595,534		(6,016,787		)	1,544,530
Total liabilities and stockholders’ equity	$	2,426,035	$	4,364,704	$	4,397,167	$	(7,767,912	)	$	3,419,994



	December 31, 2011
	(In thousands)
	WESCO International, Inc.		WESCO Distribution, Inc.		Non-Guarantor Subsidiaries		Consolidating and Eliminating Entries			Consolidated
Cash and cash equivalents	$	5	$	44,412	$	19,452	$	—		$	63,869
Trade accounts receivable, net	—		—		939,422		—			939,422
Inventories, net	—		341,423		285,544		—			626,967
Other current assets	270		32,548		74,344		—			107,162
Total current assets	275		418,383		1,318,762		—			1,737,420
Intercompany receivables, net	—		—		1,771,921		(1,771,921		)	—
Property, buildings and equipment, net	—		54,038		79,512		—			133,550
Intangible assets, net	—		6,981		149,893		—			156,874
Goodwill and other intangibles, net	—		246,125		762,002		—			1,008,127
Investments in affiliates and other noncurrent assets	2,219,323		3,422,885		31,745		(5,631,472		)	42,481
Total assets	$	2,219,598	$	4,148,412	$	4,113,835	$	(7,403,393	)	$	3,078,452
Accounts payable	$	—	$	423,509	$	219,268	$	—		$	642,777
Other current liabilities	7,797		56,035		139,237		—			203,069
Total current liabilities	7,797		479,544		358,505		—			845,846
Intercompany payables, net	668,447		1,103,474		—		(1,771,921		)	—
Long-term debt	169,054		188,081		285,787		—			642,922
Other noncurrent liabilities	28,131		163,177		52,466		—			243,774
Stockholders’ equity	1,346,169		2,214,136		3,417,077		(5,631,472		)	1,345,910
Total liabilities and stockholders’ equity	$	2,219,598	$	4,148,412	$	4,113,835	$	(7,403,393	)	$	3,078,452

WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATING STATEMENTS OF INCOME AND COMPREHENSIVE INCOME

(unaudited)



	Three Months Ended September 30, 2012
	(In thousands)
	WESCO International, Inc.		WESCO Distribution, Inc.		Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net sales	$	—	$	868,289	$	816,211		$	(28,314	)	$	1,656,186
Cost of goods sold	—		689,522		656,224			(28,314		)	1,317,432
Selling, general and administrative expenses	25		121,006		104,781			—			225,812
Depreciation and amortization	—		3,980		5,930			—			9,910
Results of affiliates’ operations	69,571		44,115		—			(113,686		)	—
Interest expense, net	6,095		3,706		2,853			—			12,654
Provision for income taxes	—		24,679		2,308			—			26,987
Net income (loss)	63,451		69,511		44,115			(113,686		)	63,391
Less: Net loss attributable to noncontrolling interest	—		—		(24		)	—			(24		)
Net income (loss) attributable to WESCO International, Inc.	$	63,451	$	69,511	$	44,139		$	(113,686	)	$	63,415
Comprehensive income:
Foreign currency translation adjustment	10,652		10,652		10,652			(21,304		)	10,652
Comprehensive income attributable to WESCO International, Inc.	$	74,103	$	80,163	$	54,791		$	(134,990	)	$	74,067



	Three Months Ended September 30, 2011
	(In thousands)
	WESCO International, Inc.			WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net sales	$	—		$	847,745		$	764,880		$	(32,249	)	$	1,580,376
Cost of goods sold	—			680,897			616,097			(32,249		)	1,264,745
Selling, general and administrative expenses	18			134,671			81,516			—			216,205
Depreciation and amortization	—			2,780			4,894			—			7,674
Results of affiliates’ operations	60,336			53,846			—			(114,182		)	—
Interest expense, net	6,428			5,573			3,078			—			15,079
Provision for income taxes	—			17,334			5,449			—			22,783
Net income (loss) attributable to WESCO International, Inc.	$	53,890		$	60,336		$	53,846		$	(114,182	)	$	53,890
Comprehensive income:
Foreign currency translation adjustment	(26,411		)	(26,411		)	(26,411		)	52,822			(26,411		)
Comprehensive income attributable to WESCO International, Inc.	$	27,479		$	33,925		$	27,435		$	(61,360	)	$	27,479

WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATING STATEMENTS OF INCOME AND COMPREHENSIVE INCOME

(unaudited)



	Nine Months Ended September 30, 2012
	(In thousands)
	WESCO International, Inc.		WESCO Distribution, Inc.		Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net sales	$	—	$	2,602,688	$	2,432,239		$	(99,989	)	$	4,934,938
Cost of goods sold	—		2,074,165		1,966,586			(99,989		)	3,940,762
Selling, general and administrative expenses	49		413,540		271,541			—			685,130
Depreciation and amortization	—		11,231		15,200			—			26,431
Results of affiliates’ operations	192,729		164,338		—			(357,067		)	—
Interest expense, net	17,417		7,667		8,009			—			33,093
Provision for income taxes	—		67,694		6,565			—			74,259
Net income (loss)	175,263		192,729		164,338			(357,067		)	175,263
Less: Net loss attributable to noncontrolling interest	—		—		(4		)	—			(4		)
Net income (loss) attributable to WESCO International, Inc.	$	175,263	$	192,729	$	164,342		$	(357,067	)	$	175,267
Comprehensive income:
Foreign currency translation adjustment	14,297		14,297		14,297			(28,594		)	14,297
Comprehensive income attributable to WESCO International, Inc.	$	189,560	$	207,026	$	178,639		$	(385,661	)	$	189,564



	Nine Months Ended September 30, 2011
	(In thousands)
	WESCO International, Inc.			WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net sales	$	—		$	2,386,968		$	2,223,588		$	(74,360	)	$	4,536,196
Cost of goods sold	—			1,913,902			1,788,124			(74,360		)	3,627,666
Selling, general and administrative expenses	62			404,112			240,002			—			644,176
Depreciation and amortization	—			8,228			14,633			—			22,861
Results of affiliates’ operations	159,957			156,191			—			(316,148		)	—
Interest expense, net	18,493			12,839			10,319			—			41,651
Provision for income taxes	—			44,121			14,319			—			58,440
Net income (loss) attributable to WESCO International, Inc.	$	141,402		$	159,957		$	156,191		$	(316,148	)	$	141,402
Comprehensive income:
Foreign currency translation adjustment	(16,685		)	(16,685		)	(16,685		)	33,370			(16,685		)
Comprehensive income attributable to WESCO International, Inc.	$	124,717		$	143,272		$	139,506		$	(282,778	)	$	124,717

WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS

(unaudited)



	Nine Months Ended September 30, 2012
	(In thousands)
	WESCO International, Inc.			WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries		Consolidated
Net cash (used) provided by operating activities	$	(8,490	)	$	201,343		$	(3,170	)	$	—	$	189,683
Investing activities:
Capital expenditures	—			(15,654		)	(3,815		)	—		(19,469		)
Acquisition payments	—			(201,123		)	—			—		(201,123		)
Other	—			51			—			—		51
Net cash used in investing activities	—			(216,726		)	(3,815		)	—		(220,541		)
Financing activities:
Net borrowings	10,957			36,589			19,259			—		66,805
Equity transactions	(2,469		)	—			—			—		(2,469		)
Other	—			10,055			—			—		10,055
Net cash provided by financing activities	8,488			46,644			19,259			—		74,391
Effect of exchange rate changes on cash and cash equivalents	—			—			235			—		235
Net change in cash and cash equivalents	(2.4		)	31,261			12,509			—		43,768
Cash and cash equivalents at the beginning of year	5			44,412			19,452			—		63,869
Cash and cash equivalents at the end of period	$	3		$	75,673		$	31,961		$	—	$	107,637



	Nine Months Ended September 30, 2011
	(In thousands)
	WESCO International, Inc.			WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries		Consolidated
Net cash provided (used) by operating activities	$	(2,450	)	$	33,256		$	41,022		$	—	$	71,828
Investing activities:
Capital expenditures	—			(21,700		)	(2,266		)	—		(23,966		)
Acquisition payments	—			(8,166		)	—			—		(8,166		)
Other	—			86			—			—		86
Net cash used in investing activities	—			(29,780		)	(2,266		)	—		(32,046		)
Financing activities:
Net (repayments) borrowings	4,973			(6,002		)	—			—		(1,029		)
Equity transactions	(2,517		)	—			—			—		(2,517		)
Other	—			8,751			—			—		8,751
Net cash provided by financing activities	2,456			2,749			—			—		5,205
Effect of exchange rate changes on cash and cash equivalents	—			—			(4,515		)	—		(4,515		)
Net change in cash and cash equivalents	6			6,225			34,241			—		40,472
Cash and cash equivalents at the beginning of year	1			32,342			21,234			—		53,577
Cash and cash equivalents at the end of period	$	7		$	38,567		$	55,475		$	—	$	94,049

SUBSEQUENT EVENTS	9 Months Ended
SUBSEQUENT EVENTS	Sep. 30, 2012
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	SUBSEQUENT EVENTS On October 15, 2012, WESCO entered into a definitive agreement to acquire EECOL Electric Corporation, headquartered in Calgary, Alberta, Canada, and various affiliated companies for a purchase price of approximately CAD$1.14 billion. EECOL Electric is one of Canada's premier full-line distributors of electrical equipment, products and services with approximately $0.9 billion in annual sales, 57 locations across Canada and 20 in South America, and more than 20,000 customers. Consummation of the transaction is subject to certain conditions, including approval under the Canadian Competition Act. The acquisition is expected to be financed utilizing a new institutional term loan to be entered into on or before closing, as well as WESCO's existing credit facilities. Closing is expected to occur during the fourth quarter of 2012.

ACCOUNTING POLICIES (Policies)	9 Months Ended
ACCOUNTING POLICIES (Policies)	Sep. 30, 2012
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The unaudited condensed consolidated financial statements of WESCO have been prepared in accordance with Rule 10-01 of Regulation S-X of the Securities and Exchange Commission (the “SEC”). The unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in WESCO’s 2011 Annual Report on Form 10-K filed with the SEC. The December 31, 2011 condensed consolidated balance sheet data was derived from audited financial statements but does not include all disclosures required by accounting principles generally accepted in the United States. The unaudited condensed consolidated balance sheet as of September 30, 2012, the unaudited condensed consolidated statements of income for the three and nine months ended September 30, 2012 and 2011, respectively, and the unaudited condensed consolidated statements of cash flows for the nine months ended September 30, 2012 and 2011, respectively, in the opinion of management, have been prepared on the same basis as the audited consolidated financial statements and include all adjustments necessary for the fair statement of the results of the interim periods. All adjustments reflected in the unaudited condensed consolidated financial statements are of a normal recurring nature unless indicated. Results for the interim periods presented are not necessarily indicative of the results to be expected for the full year.
Reclassification	Reclassification Certain prior period amounts have been reclassified to conform with the current period's financial statement presentation.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company measures the fair value of financial assets and liabilities based on the guidance of ASC 820, "Fair Value Measurements and Disclosures," which defines fair value, establishes a framework for measuring fair value, and expands disclosures about fair value measurements. ASC 820 establishes a fair value hierarchy, which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. ASC 820 describes three levels of inputs that may be used to measure fair value: Level 1 inputs are quoted prices in active markets for identical assets or liabilities. Level 2 inputs include inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices in active markets for similar assets and liabilities, quoted prices for identical or similar assets or liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of assets or liabilities. Level 3 inputs are unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions. At September 30, 2012, the carrying value of WESCO’s 7.50% Senior Subordinated Notes due 2017 (the "2017 Notes") and 6.0% Convertible Senior Debentures due 2029 (the "2029 Debentures") was $494.9 million and the fair value was approximately $892.9 million. At December 31, 2011, the carrying value of WESCO’s 2017 Notes and 2029 Debentures was $495.0 million and the fair value was approximately $850.9 million. The fair value of WESCO’s 2017 Notes and 2029 Debentures is based on quoted prices in active markets and is therefore classified as Level 1 within the valuation hierarchy. The reported carrying amounts of WESCO’s other debt instruments approximate their fair values and are classified as Level 2 within the valuation hierarchy. Other debt instruments included in Level 2 are valued using a market approach, utilizing interest rates and other relevant information generated by market transactions involving similar instruments.

- Definition

Disclosure of accounting policy regarding (1) the principles it follows in consolidating or combining the separate financial statements, including the principles followed in determining the inclusion or exclusion of subsidiaries or other entities in the consolidated or combined financial statements and (2) its treatment of interests (for example, common stock, a partnership interest or other means of exerting influence) in other entities, for example consolidation or use of the equity or cost methods of accounting. The accounting policy may also address the accounting treatment for intercompany accounts and transactions, noncontrolling interest, and the income statement treatment in consolidation for issuances of stock by a subsidiary.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 140
-Paragraph 46
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 2-6
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 46R
-Paragraph 14, 15
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 18
-Paragraph 5, 6, 16-19
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 18
-Paragraph 20
-Subparagraph a(2)
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Emerging Issues Task Force (EITF)
-Number 96-16
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Emerging Issues Task Force (EITF)
-Number 97-2
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 3A
-Section 02, 03

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph k
-Article 1

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 46R
-Paragraph 4
-Subparagraph c
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 46R
-Paragraph 4
-Subparagraph d
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6367646&loc=d3e18780-107790

Reference 13: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-URI http://asc.fasb.org/section&trid=2197723

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 15: http://www.xbrl.org/2003/role/presentationRef
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-URI http://asc.fasb.org/extlink&oid=6921930&loc=d3e5614-111684

Reference 16: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-Paragraph 2
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-URI http://asc.fasb.org/extlink&oid=6959686&loc=d3e355033-122828

Reference 17: http://www.xbrl.org/2003/role/presentationRef
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Reference 18: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=6382870&loc=d3e33801-111570

Reference 19: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 325
-SubTopic 20
-URI http://asc.fasb.org/subtopic&trid=2197087

+ Details

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 44A, 44B
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 15C, 15D
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 15A
-Subparagraph a-d
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 15B
-Subparagraph a, b
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 3, 10, 14, 15
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 157
-Paragraph 32, 33, 34
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 159
-Paragraph 17-22, 27, 28
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
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Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 12: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Paragraph 16
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Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19296-110258

+ Details

ACQUISITIONS (Tables)

9 Months Ended

Sep. 30, 2012

Business Combinations [Abstract]

Schedule of Business Acquisitions, by Acquisition [Table Text Block]

The following table sets forth the consideration paid for acquisitions:



Nine Months Ended September 30	2012			2011
(In thousands)
Details of acquisitions:
Fair value of assets acquired	$	215,303		$	11,187
Fair value of liabilities assumed	(14,180		)	(3,021		)
Cash paid for acquisitions	$	201,123		$	8,166

- Definition

Tabular disclosure of a material business combination completed during the period, including background, timing, and recognized assets and liabilities. This table does not include leveraged buyouts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 141
-Paragraph 51
-Subparagraph a
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 141
-Paragraph 52
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 141R
-Paragraph 68
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 141R
-Appendix F
-Paragraph F4
-Subparagraph e

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
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Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6972119&loc=d3e1486-128463

+ Details

STOCK-BASED COMPENSATION (Tables)

9 Months Ended

Sep. 30, 2012

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]



	Three Months Ended September 30,				Nine Months Ended September 30,
	2012		2011		2012		2011
Stock-settled appreciation rights granted	850		15,156		257,932		399,330
Restricted stock units granted	2,400		—		74,724		53,852
Performance-based awards granted	—		—		46,804		—
Risk free interest rate	0.6	%	1.0	%	0.9	%	2.3	%
Expected life (in years)	5.0		5.0		5.0		5.0
Expected volatility	50	%	48	%	50	%	49	%

Schedule of Share-based Compensation, Stock Options and Stock Appreciation Rights Award Activity [Table Text Block]

The following table sets forth a summary of stock options and stock-settled stock appreciation rights and related information for the nine months ended September 30, 2012:



	Awards		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (In Years)	Aggregate Intrinsic Value (In thousands)
Outstanding at December 31, 2011	4,266,533		$	39.64
Granted	257,932		64.12
Exercised	(697,037	)	32.46
Forfeited	(36,061	)	49.43
Outstanding at September 30, 2012	3,791,367		42.54		5.8	$	72,535
Exercisable at September 30, 2012	3,084,703		$	40.06	5.1	$	66,470

Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block]

The following table sets forth a summary of restricted stock units and related information for the nine months ended September 30, 2012:



	Awards		Weighted Average Fair Value
Unvested at December 31, 2011	203,291		$	37.16
Granted	74,724		64.27
Vested	(78,305	)	25.37
Forfeited	(8,684	)	45.02
Unvested at September 30, 2012	191,026		$	52.24

Schedule of Nonvested Performance-based Units Activity [Table Text Block]

The following table sets forth a summary of performance-based awards for the nine months ended September 30, 2012:



	Awards		Weighted Average Fair Value
Unvested at December 31, 2011	—		—
Granted	46,804		$	75.72
Vested	—		—
Forfeited	(304	)	75.72
Unvested at June 30, 2012	46,500		$	75.72

Schedule of Share-based Payment Award, Performance-based Awards, Valuation Assumptions [Table Text Block]

The fair value of the performance shares granted during the nine months ended September 30, 2012 were estimated using the following weighted-average assumptions:



Weighted Average Assumptions
Grant date share price	$	64.33
WESCO expected volatility	41.97		%
Peer group median volatility	33.40		%
Risk-free interest rate	0.40		%
Correlation	135.4		%

EARNINGS PER SHARE (Tables)

9 Months Ended

Sep. 30, 2012

Earnings Per Share [Abstract]

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

The following table sets forth the details of basic and diluted earnings per share:



	Three Months Ended
	September 30,
	2012		2011
Net income attributable to WESCO International, Inc.	$	63,415	$	53,890
Weighted average common shares outstanding used in computing basic earnings per share	43,705		43,289
Common shares issuable upon exercise of dilutive equity awards	1,032		976
Common shares issuable from contingently convertible debentures (see below for basis of calculation)	6,036		4,206
Weighted average common shares outstanding and common share equivalents used in computing diluted earnings per share	50,773		48,471
Earnings per share attributable to WESCO International, Inc.
Basic	$	1.45	$	1.24
Diluted	$	1.25	$	1.11



	Nine Months Ended
	September 30,
	2012		2011
Net income attributable to WESCO International, Inc.	$	175,267	$	141,402
Weighted average common shares outstanding used in computing basic earnings per share	43,596		43,181
Common shares issuable upon exercise of dilutive equity awards	1,199		1,202
Common shares issuable from contingently convertible debentures (see below for basis of calculation)	6,262		5,400
Weighted average common shares outstanding and common share equivalents used in computing diluted earnings per share	51,057		49,783
Earnings per share attributable to WESCO International, Inc.
Basic	$	4.02	$	3.27
Diluted	$	3.43	$	2.84

OTHER FINANCIAL INFORMATION (Tables)

9 Months Ended

Sep. 30, 2012

Condensed Financial Information [Abstract]

Condensed Financial Information Statements Of Financial Condition [Text Block]



	September 30, 2012
	(In thousands)
	WESCO International, Inc.		WESCO Distribution, Inc.		Non-Guarantor Subsidiaries		Consolidating and Eliminating Entries			Consolidated
Cash and cash equivalents	$	3	$	75,673	$	31,961	$	—		$	107,637
Trade accounts receivable, net	—		—		1,020,454		—			1,020,454
Inventories, net	—		337,316		325,448		—			662,764
Other current assets	—		38,423		76,647		—			115,070
Total current assets	3		451,412		1,454,510		—			1,905,925
Intercompany receivables, net	—		—		1,751,125		(1,751,125		)	—
Property, buildings and equipment, net	—		59,543		81,455		—			140,998
Intangible assets, net	—		6,360		198,212		—			204,572
Goodwill and other intangibles, net	—		246,125		880,876		—			1,127,001
Investments in affiliates and other noncurrent assets	2,426,032		3,601,264		30,989		(6,016,787		)	41,498
Total assets	$	2,426,035	$	4,364,704	$	4,397,167	$	(7,767,912	)	$	3,419,994
Accounts payable	$	—	$	444,291	$	248,886	$	—		$	693,177
Other current liabilities	2,578		57,161		157,120		—			216,859
Total current liabilities	2,578		501,452		406,006		—			910,036
Intercompany payables, net	679,405		1,071,720		—		(1,751,125		)	—
Long-term debt	171,244		187,988		337,526		—			696,758
Other noncurrent liabilities	28,126		182,443		58,101		—			268,670
Stockholders’ equity	1,544,682		2,421,101		3,595,534		(6,016,787		)	1,544,530
Total liabilities and stockholders’ equity	$	2,426,035	$	4,364,704	$	4,397,167	$	(7,767,912	)	$	3,419,994



	December 31, 2011
	(In thousands)
	WESCO International, Inc.		WESCO Distribution, Inc.		Non-Guarantor Subsidiaries		Consolidating and Eliminating Entries			Consolidated
Cash and cash equivalents	$	5	$	44,412	$	19,452	$	—		$	63,869
Trade accounts receivable, net	—		—		939,422		—			939,422
Inventories, net	—		341,423		285,544		—			626,967
Other current assets	270		32,548		74,344		—			107,162
Total current assets	275		418,383		1,318,762		—			1,737,420
Intercompany receivables, net	—		—		1,771,921		(1,771,921		)	—
Property, buildings and equipment, net	—		54,038		79,512		—			133,550
Intangible assets, net	—		6,981		149,893		—			156,874
Goodwill and other intangibles, net	—		246,125		762,002		—			1,008,127
Investments in affiliates and other noncurrent assets	2,219,323		3,422,885		31,745		(5,631,472		)	42,481
Total assets	$	2,219,598	$	4,148,412	$	4,113,835	$	(7,403,393	)	$	3,078,452
Accounts payable	$	—	$	423,509	$	219,268	$	—		$	642,777
Other current liabilities	7,797		56,035		139,237		—			203,069
Total current liabilities	7,797		479,544		358,505		—			845,846
Intercompany payables, net	668,447		1,103,474		—		(1,771,921		)	—
Long-term debt	169,054		188,081		285,787		—			642,922
Other noncurrent liabilities	28,131		163,177		52,466		—			243,774
Stockholders’ equity	1,346,169		2,214,136		3,417,077		(5,631,472		)	1,345,910
Total liabilities and stockholders’ equity	$	2,219,598	$	4,148,412	$	4,113,835	$	(7,403,393	)	$	3,078,452

Condensed Financial Information Statement Of Income [Text Block]



	Three Months Ended September 30, 2012
	(In thousands)
	WESCO International, Inc.		WESCO Distribution, Inc.		Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net sales	$	—	$	868,289	$	816,211		$	(28,314	)	$	1,656,186
Cost of goods sold	—		689,522		656,224			(28,314		)	1,317,432
Selling, general and administrative expenses	25		121,006		104,781			—			225,812
Depreciation and amortization	—		3,980		5,930			—			9,910
Results of affiliates’ operations	69,571		44,115		—			(113,686		)	—
Interest expense, net	6,095		3,706		2,853			—			12,654
Provision for income taxes	—		24,679		2,308			—			26,987
Net income (loss)	63,451		69,511		44,115			(113,686		)	63,391
Less: Net loss attributable to noncontrolling interest	—		—		(24		)	—			(24		)
Net income (loss) attributable to WESCO International, Inc.	$	63,451	$	69,511	$	44,139		$	(113,686	)	$	63,415
Comprehensive income:
Foreign currency translation adjustment	10,652		10,652		10,652			(21,304		)	10,652
Comprehensive income attributable to WESCO International, Inc.	$	74,103	$	80,163	$	54,791		$	(134,990	)	$	74,067



	Three Months Ended September 30, 2011
	(In thousands)
	WESCO International, Inc.			WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net sales	$	—		$	847,745		$	764,880		$	(32,249	)	$	1,580,376
Cost of goods sold	—			680,897			616,097			(32,249		)	1,264,745
Selling, general and administrative expenses	18			134,671			81,516			—			216,205
Depreciation and amortization	—			2,780			4,894			—			7,674
Results of affiliates’ operations	60,336			53,846			—			(114,182		)	—
Interest expense, net	6,428			5,573			3,078			—			15,079
Provision for income taxes	—			17,334			5,449			—			22,783
Net income (loss) attributable to WESCO International, Inc.	$	53,890		$	60,336		$	53,846		$	(114,182	)	$	53,890
Comprehensive income:
Foreign currency translation adjustment	(26,411		)	(26,411		)	(26,411		)	52,822			(26,411		)
Comprehensive income attributable to WESCO International, Inc.	$	27,479		$	33,925		$	27,435		$	(61,360	)	$	27,479

WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATING STATEMENTS OF INCOME AND COMPREHENSIVE INCOME

(unaudited)



	Nine Months Ended September 30, 2012
	(In thousands)
	WESCO International, Inc.		WESCO Distribution, Inc.		Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net sales	$	—	$	2,602,688	$	2,432,239		$	(99,989	)	$	4,934,938
Cost of goods sold	—		2,074,165		1,966,586			(99,989		)	3,940,762
Selling, general and administrative expenses	49		413,540		271,541			—			685,130
Depreciation and amortization	—		11,231		15,200			—			26,431
Results of affiliates’ operations	192,729		164,338		—			(357,067		)	—
Interest expense, net	17,417		7,667		8,009			—			33,093
Provision for income taxes	—		67,694		6,565			—			74,259
Net income (loss)	175,263		192,729		164,338			(357,067		)	175,263
Less: Net loss attributable to noncontrolling interest	—		—		(4		)	—			(4		)
Net income (loss) attributable to WESCO International, Inc.	$	175,263	$	192,729	$	164,342		$	(357,067	)	$	175,267
Comprehensive income:
Foreign currency translation adjustment	14,297		14,297		14,297			(28,594		)	14,297
Comprehensive income attributable to WESCO International, Inc.	$	189,560	$	207,026	$	178,639		$	(385,661	)	$	189,564



	Nine Months Ended September 30, 2011
	(In thousands)
	WESCO International, Inc.			WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net sales	$	—		$	2,386,968		$	2,223,588		$	(74,360	)	$	4,536,196
Cost of goods sold	—			1,913,902			1,788,124			(74,360		)	3,627,666
Selling, general and administrative expenses	62			404,112			240,002			—			644,176
Depreciation and amortization	—			8,228			14,633			—			22,861
Results of affiliates’ operations	159,957			156,191			—			(316,148		)	—
Interest expense, net	18,493			12,839			10,319			—			41,651
Provision for income taxes	—			44,121			14,319			—			58,440
Net income (loss) attributable to WESCO International, Inc.	$	141,402		$	159,957		$	156,191		$	(316,148	)	$	141,402
Comprehensive income:
Foreign currency translation adjustment	(16,685		)	(16,685		)	(16,685		)	33,370			(16,685		)
Comprehensive income attributable to WESCO International, Inc.	$	124,717		$	143,272		$	139,506		$	(282,778	)	$	124,717

Condensed Financial Information Statements Of Cash Flows [Text Block]



	Nine Months Ended September 30, 2012
	(In thousands)
	WESCO International, Inc.			WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries		Consolidated
Net cash (used) provided by operating activities	$	(8,490	)	$	201,343		$	(3,170	)	$	—	$	189,683
Investing activities:
Capital expenditures	—			(15,654		)	(3,815		)	—		(19,469		)
Acquisition payments	—			(201,123		)	—			—		(201,123		)
Other	—			51			—			—		51
Net cash used in investing activities	—			(216,726		)	(3,815		)	—		(220,541		)
Financing activities:
Net borrowings	10,957			36,589			19,259			—		66,805
Equity transactions	(2,469		)	—			—			—		(2,469		)
Other	—			10,055			—			—		10,055
Net cash provided by financing activities	8,488			46,644			19,259			—		74,391
Effect of exchange rate changes on cash and cash equivalents	—			—			235			—		235
Net change in cash and cash equivalents	(2.4		)	31,261			12,509			—		43,768
Cash and cash equivalents at the beginning of year	5			44,412			19,452			—		63,869
Cash and cash equivalents at the end of period	$	3		$	75,673		$	31,961		$	—	$	107,637



	Nine Months Ended September 30, 2011
	(In thousands)
	WESCO International, Inc.			WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries		Consolidated
Net cash provided (used) by operating activities	$	(2,450	)	$	33,256		$	41,022		$	—	$	71,828
Investing activities:
Capital expenditures	—			(21,700		)	(2,266		)	—		(23,966		)
Acquisition payments	—			(8,166		)	—			—		(8,166		)
Other	—			86			—			—		86
Net cash used in investing activities	—			(29,780		)	(2,266		)	—		(32,046		)
Financing activities:
Net (repayments) borrowings	4,973			(6,002		)	—			—		(1,029		)
Equity transactions	(2,517		)	—			—			—		(2,517		)
Other	—			8,751			—			—		8,751
Net cash provided by financing activities	2,456			2,749			—			—		5,205
Effect of exchange rate changes on cash and cash equivalents	—			—			(4,515		)	—		(4,515		)
Net change in cash and cash equivalents	6			6,225			34,241			—		40,472
Cash and cash equivalents at the beginning of year	1			32,342			21,234			—		53,577
Cash and cash equivalents at the end of period	$	7		$	38,567		$	55,475		$	—	$	94,049

ORGANIZATION (Details)	9 Months Ended
ORGANIZATION (Details)	Sep. 30, 2012 branches countries customers distribution_centers
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Customers (in customers) \| customers	65,000
Full service branches (in branches) \| branches	400
Distribution centers (in distribution centers) \| distribution_centers	8
Additional countries (in countries) \| countries	11

ACCOUNTING POLICIES (Details) - USD ($) $ in Millions	Sep. 30, 2012	Dec. 31, 2011
Accounting Policies [Abstract]
Fixed Rate Debt, Par Value	$ 494.9	$ 495.0
Fixed Rate Debt, Fair Value Disclosures	$ 892.9	$ 850.9

ACQUISITIONS - SCHEDULE OF BUSINESS ACQUISITIONS (Details) - USD ($) $ in Thousands	Dec. 31, 2011	Dec. 31, 2010
Business Acquisition [Line Items]
Fair value of assets acquired	$ 215,303	$ 11,187
Fair value of liabilities assumed	(14,180)	(3,021)
Cash paid for acquisitions	$ 201,123	$ 8,166

ACQUISITIONS - ACQUISITIONS (Details) $ in Millions				2 Months Ended	9 Months Ended	12 Months Ended
ACQUISITIONS - ACQUISITIONS (Details) $ in Millions	Jul. 10, 2012	Jul. 05, 2012	Jan. 03, 2012	Mar. 14, 2011 USD ($)	Sep. 30, 2012 USD ($) yr	Dec. 31, 2011 USD ($)
Business Acquisition [Line Items]
Business Acquisition, Purchase Price Allocation, Goodwill Amount					$ 114.9
Business Acquisition, Purchase Price Allocation, Intangible Assets					57.0
Acquired Intangible Asset, Trademark					5.1
RECO, LLC [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition				March 14, 2011
Business Acquisition, Revenue Reported by Acquired Entity for Last Annual Period						$ 25.0
Business Acquisition, Purchase Price Allocation, Goodwill Amount				$ 6.0
RS Electronics [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition			January 3, 2012
Business Acquisition, Revenue Reported by Acquired Entity for Last Annual Period					60.0
Trydor Industries (Canada), Ltd. [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition		July 5, 2012
Business Acquisition, Revenue Reported by Acquired Entity for Last Annual Period						35.0
Conney Safety Products, LLC [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition	July 10, 2012
Business Acquisition, Revenue Reported by Acquired Entity for Last Annual Period						$ 85.0
Customer Relationships [Member]
Business Acquisition [Line Items]
Business Acquisition, Purchase Price Allocation, Amortizable Intangible Assets					$ 49.2
Customer Relationships [Member] \| Minimum [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Asset, Weighted Average Useful Life \| yr					10
Customer Relationships [Member] \| Maximum [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Asset, Weighted Average Useful Life \| yr					12
Supplier Relationships [Member]
Business Acquisition [Line Items]
Business Acquisition, Purchase Price Allocation, Amortizable Intangible Assets					$ 2.7
Acquired Finite-lived Intangible Asset, Weighted Average Useful Life \| yr					10
Trademarks [Member] \| Minimum [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Asset, Weighted Average Useful Life \| yr					4
Trademarks [Member] \| Maximum [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Asset, Weighted Average Useful Life \| yr					15

SCHEDULE OF SHARE-BASED COMPENSATION, STOCK OPTIONS AND STOCK APPRECIATION RIGHTS AWARD ACTIVITY (Details) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2012 USD ($) yr $ / shares shares
Share-based Compensation Arrangement By Share-based Payment Award, Options and Stock Appreciation Rights, Outstanding [Roll Forward]
Beginning of Year (in shares) \| shares	4,266,533
Grants in Period (in shares) \| shares	257,932
Exercises in Period (in shares) \| shares	697,037
Forfeitures in Period (in shares) \| shares	36,061
End of Period (in shares) \| shares	3,791,367
Exercisable (in shares) \| shares	3,084,703
Weighted Average Exercise Price, Beginning of Year (in dollars per share) \| $ / shares	$ 39.64
Weighted Average Exercise Price, Grants in Period (in dollars per share) \| $ / shares	64.12
Weighted Average Exercise Price, Exercises in Period (in dollars per share) \| $ / shares	32.46
Weighted Average Exercise Price, Forfeitures in Period (in dollars per share) \| $ / shares	49.43
Weighted Average Exercise Price, End of Period (in dollars per share) \| $ / shares	42.54
Weighted Average Exercise Price, Exercisable (in dollars per share) \| $ / shares	$ 40.06
Weighted Average Remaining Contractual Term, Outstanding (in years) \| yr	5.8
Weighted Average Remaining Contractual Term, Exercisable (in years) \| yr	5.1
Aggregate Intrinsic Value, Outstanding \| $	$ 72,535
Aggregate Intrinsic Value, Exercisable \| $	$ 66,470

SCHEDULE OF SHARE-BASED PAYMENT AWARD, VALUATION ASSUMPTIONS (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2012 yr shares	Jun. 30, 2011 yr shares	Sep. 30, 2012 yr shares	Sep. 30, 2011 yr shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk free interest rate	0.60%	1.00%	0.90%	2.30%
Expected life (in years) \| yr	5.0	5.0	5.0	5.0
WESCO expected volatility	50.00%	48.00%	50.00%	49.00%
Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	850	15,156	257,932	399,330
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	2,400	0	74,724	53,852
Performance-based Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	0	0	46,804	0

SUMMARY OF RESTRICTED STOCK UNITS (Details) - Restricted Stock Units (RSUs) [Member] - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Jun. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Unvested (in shares)	191,026		191,026		203,291
Granted (in shares)	2,400	0	74,724	53,852
Vested (in shares)			(78,305)
Forfeited (in shares)			(8,684)
Unvested, Weighted Average Fair Value (in dollars per share)	$ 52.24		$ 52.24		$ 37.16
Granted, Weighted Average Fair Value (in dollars per share)	62.49		64.27	$ 60.05
Vested in Period, Weighted Average Fair Value (in dollars per share)			25.37
Forfeited in Period, Weighted Average Fair Value (in dollars per share)	$ 45.02		$ 45.02

SUMMARY OF PERFORMANCE-BASED AWARDS (Details) - Performance-based Awards [Member] - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Jun. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Unvested (in shares)	46,500		46,500		0
Granted (in shares)	0	0	46,804	0
Vested (in shares)			0
Forfeited (in shares)			(304)
Unvested, Weighted Average Fair Value (in dollars per share)	$ 75.72		$ 75.72		$ 0.00
Granted, Weighted Average Fair Value (in dollars per share)			75.72
Vested in Period, Weighted Average Fair Value (in dollars per share)			0.00
Forfeited in Period, Weighted Average Fair Value (in dollars per share)	$ 75.72		$ 75.72

SCHEDULE OF SHARE-BASED PAYMENT AWARD, PERFORMANCE-BASED AWARDS, VALUATION ASSUMPTIONS (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Jun. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
WESCO expected volatility	50.00%	48.00%	50.00%	49.00%
Risk free interest rate	0.60%	1.00%	0.90%	2.30%
Performance-based Awards - Peer Group Total Shareholder Return [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date share price			$ 64.33
WESCO expected volatility			41.97%
Peer group mean volatility			33.40%
Risk free interest rate			0.40%
Correlation			135.40%

STOCK-BASED COMPENSATION (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Jun. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 3,200	$ 2,900	$ 11,722	$ 12,360
Total unrecognized compensation cost	$ 21,400		21,400
Compensation cost expected to be recognized over the remainder of 2012			3,400
Compensation cost expected to be recognized in 2013			11,400
Compensation cost expected to be recognized in 2014			5,900
Compensation cost expected to be recognized in 2015			700
Total intrinsic value of awards exercised			22,400	12,000
Cash received from exercise of options			200
Tax benefit associated with exercise of awards			$ 5,400	$ 3,500
Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Weighted Average Fair Value (in dollars per share)	$ 24.33	$ 16.42	$ 27.89	$ 26.47
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Weighted Average Fair Value (in dollars per share)	$ 62.49		$ 64.27	$ 60.05
Performance-based awards outstanding (in shares)	191,026		191,026		203,291
Performance-based Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Weighted Average Fair Value (in dollars per share)			$ 75.72
Performance-based awards outstanding (in shares)	46,500		46,500		0
Performance-based Awards - Peer Group Total Shareholder Return [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance-based awards outstanding (in shares)	23,250		23,250

SCHEDULE OF EARNINGS PER SHARE, BASIC AND DILUTED (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Jun. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Earnings Per Share [Abstract]
Net income attributable to WESCO International, Inc.	$ 63,415	$ 53,890	$ 175,267	$ 141,402
Weighted average common shares outstanding used in computing basic earnings per share (in shares)	43,705,000	43,289,000	43,596,000	43,181,000
Common shares issuable upon exercise of dilutive stock options (in shares)	1,032,000	976,000	1,199,000	1,202,000
Common shares issuable from contingently convertible debentures (in shares)	6,036,000	4,206,000	6,262,000	5,400,000
Weighted average common shares outstanding and common share equivalents used in computing diluted earnings per share (in shares)	50,773,000	48,471,000	51,057,000	49,783,000
Earnings Per Share, Basic and Diluted [Abstract]
Basic (in dollars per share)	$ 1.45	$ 1.24	$ 4.02	$ 3.27
Diluted (in dollars per share)	$ 1.25	$ 1.11	$ 3.43	$ 2.84

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 36, 37, 38
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 5
-Section 03
-Paragraph 20

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Article 7
-Paragraph 18

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph 21
-Article 9

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.21)
-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

Reference 6: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6920599&loc=d3e1252-109256

Reference 7: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 55
-Paragraph 52
-URI http://asc.fasb.org/extlink&oid=6945512&loc=d3e4984-109258

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
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-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.23)
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.19)
-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Emerging Issues Task Force (EITF)
-Number 07-4
-Paragraph 4
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

+ References + Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Emerging Issues Task Force (EITF)
-Number 87-21
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 38
-Subparagraph a
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 130
-Paragraph 10, 15
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 28, 29, 30
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 5
-Section 03
-Paragraph 19

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph 20
-Article 9

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Net Income
-URI http://asc.fasb.org/extlink&oid=6518256

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Other Comprehensive Income
-URI http://asc.fasb.org/extlink&oid=6519514

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.18)
-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.19)
-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6920043&loc=d3e565-108580

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.22)
-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 38
-Subparagraph d
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 16: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph A7
-Appendix A

+ Details

- Definition

The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

+ References + Details

- Definition

Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 171
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 40
-Subparagraph a
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 8
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=6920599&loc=d3e1448-109256

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Weighted-Average Number of Common Shares Outstanding
-URI http://asc.fasb.org/extlink&oid=6528421

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Emerging Issues Task Force (EITF)
-Number 07-4
-Paragraph 4
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

EARNINGS PER SHARE (Details) - $ / shares	3 Months Ended		9 Months Ended
EARNINGS PER SHARE (Details) - $ / shares	Sep. 30, 2012	Jun. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Convertible Senior Debentures Due in 2029 [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.00%		6.00%
Convertible Senior Debentures Due in 2026 [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	1.75%		1.75%
Stock Appreciation Rights (SARs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount			1,000,000	1,200,000
Antidilutive Securities Excluded from Computation of Earnings Per Share, Weighted Average Exercise Price (in dollars per share)			$ 64	$ 62
Convertible Debt Securities [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Effect of Dilutive Securities on Earnings Per Share (in dollars per share)	$ (0.17)	$ (0.11)	(0.48)	$ (0.35)
Convertible Debt Securities [Member] \| Convertible Senior Debentures Due in 2029 [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Debt Instrument, Convertible, Conversion Price (in dollars per share)	$ 28.87		$ 28.87
Earnings Per Share Dilution Limit (in shares)			11,949,513

EMPLOYEE BENEFIT PLANS (Details) - USD ($) $ in Millions	9 Months Ended
EMPLOYEE BENEFIT PLANS (Details) - USD ($) $ in Millions	Sep. 30, 2012	Sep. 30, 2011
Schedule of Employee Benefit Plans [Line Items]
Defined Contribution Plan, Cost Recognized	$ 24.2	$ 19.5
UNITED STATES
Schedule of Employee Benefit Plans [Line Items]
Defined Contribution Plan Employer Matching Contribution Percent	50.00%
Defined Contribution Plan Maximum Annual Contribution Per Employee Percent	6.00%
Minimum [Member] \| CANADA
Schedule of Employee Benefit Plans [Line Items]
Defined Contribution Plan Maximum Annual Contribution Per Employee Percent	1.00%
Maximum [Member] \| CANADA
Schedule of Employee Benefit Plans [Line Items]
Defined Contribution Plan Maximum Annual Contribution Per Employee Percent	7.00%

COMMITMENTS AND CONTINGENCIES (Details) $ in Millions	9 Months Ended
COMMITMENTS AND CONTINGENCIES (Details) $ in Millions	Sep. 30, 2012 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Loss Contingency, Damages Sought, Value	$ 50

- Definition

The value (monetary amount) of the award the plaintiff seeks in the legal matter.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
-Paragraph 9
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
-Paragraph 11
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
-Paragraph 10
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6952336&loc=d3e14326-108349

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6952336&loc=d3e14435-108349

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 9
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6952336&loc=d3e14557-108349

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
-Paragraph 12
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

INCOME TAXES (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
INCOME TAXES (Details) - USD ($) $ in Millions	Sep. 30, 2012	Jun. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Income Tax Disclosure [Abstract]
Effective tax rate	29.90%	29.70%	29.80%	29.20%
Federal statutory rate			35.00%
Discrete adjustments			$ 3.2	$ 2.1
Unrecognized tax benefits	$ 20.1		20.1		$ 20.9
Deferred tax asset					23.1
Unrecognized tax benefits that would impact effective tax rate	20.2		20.2		19.7
Significant change in unrecognized tax benefits that is reasonably possible	15.5		15.5
Liability for interest related to uncertain tax positions	$ 8.1		8.1		$ 11.4
Decrease in interest related to unrecognized tax benefits			$ (3.3)

OTHER FINANCIAL INFORMATION (Details) $ in Millions	Sep. 30, 2012 USD ($)
2017 Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 150.0
Debt Instrument, Interest Rate, Stated Percentage	7.50%
Convertible Senior Debentures Due in 2029 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 344.9

CONDENSED CONSOLIDATED BALANCE SHEETS (Details) - USD ($) $ in Thousands	Sep. 30, 2012	Dec. 31, 2011	Jun. 30, 2011	Dec. 31, 2010
Condensed Financial Information [Line Items]
Cash and cash equivalents	$ 107,637	$ 63,869	$ 94,049	$ 53,577
Trade accounts receivable, net	1,020,454	939,422
Inventories, net	662,764	626,967
Other current assets	115,070	107,162
Total current assets	1,905,925	1,737,420
Intercompany receivables, net	0	0
Property, buildings and equipment, net	140,998	133,550
Intangible assets, net	204,572	156,874
Goodwill and other intangibles, net	1,127,001	1,008,127
Investments in affiliates and other noncurrent assets	41,498	42,481
Total assets	3,419,994	3,078,452
Accounts payable	693,177	642,777
Other current liabilities	216,859	203,069
Total current liabilities	910,036	845,846
Intercompany payables, net	0	0
Long-term debt	696,758	642,922
Other noncurrent liabilities	268,670	243,774
Total stockholders' equity	1,544,530	1,345,910
Total liabilities and stockholders' equity	3,419,994	3,078,452
Parent Company [Member]
Condensed Financial Information [Line Items]
Cash and cash equivalents	3	5	7	1
Trade accounts receivable, net	0	0
Inventories, net	0	0
Other current assets	0	270
Total current assets	3	275
Intercompany receivables, net	0	0
Property, buildings and equipment, net	0	0
Intangible assets, net	0	0
Goodwill and other intangibles, net	0	0
Investments in affiliates and other noncurrent assets	2,426,032	2,219,323
Total assets	2,426,035	2,219,598
Accounts payable	0	0
Other current liabilities	2,578	7,797
Total current liabilities	2,578	7,797
Intercompany payables, net	679,405	668,447
Long-term debt	171,244	169,054
Other noncurrent liabilities	28,126	28,131
Total stockholders' equity	1,544,682	1,346,169
Total liabilities and stockholders' equity	2,426,035	2,219,598
Guarantor Subsidiaries [Member]
Condensed Financial Information [Line Items]
Cash and cash equivalents	75,673	44,412	38,567	32,342
Trade accounts receivable, net	0	0
Inventories, net	337,316	341,423
Other current assets	38,423	32,548
Total current assets	451,412	418,383
Intercompany receivables, net	0	0
Property, buildings and equipment, net	59,543	54,038
Intangible assets, net	6,360	6,981
Goodwill and other intangibles, net	246,125	246,125
Investments in affiliates and other noncurrent assets	3,601,264	3,422,885
Total assets	4,364,704	4,148,412
Accounts payable	444,291	423,509
Other current liabilities	57,161	56,035
Total current liabilities	501,452	479,544
Intercompany payables, net	1,071,720	1,103,474
Long-term debt	187,988	188,081
Other noncurrent liabilities	182,443	163,177
Total stockholders' equity	2,421,101	2,214,136
Total liabilities and stockholders' equity	4,364,704	4,148,412
Non-Guarantor Subsidiaries [Member]
Condensed Financial Information [Line Items]
Cash and cash equivalents	31,961	19,452	55,475	21,234
Trade accounts receivable, net	1,020,454	939,422
Inventories, net	325,448	285,544
Other current assets	76,647	74,344
Total current assets	1,454,510	1,318,762
Intercompany receivables, net	1,751,125	1,771,921
Property, buildings and equipment, net	81,455	79,512
Intangible assets, net	198,212	149,893
Goodwill and other intangibles, net	880,876	762,002
Investments in affiliates and other noncurrent assets	30,989	31,745
Total assets	4,397,167	4,113,835
Accounts payable	248,886	219,268
Other current liabilities	157,120	139,237
Total current liabilities	406,006	358,505
Intercompany payables, net	0	0
Long-term debt	337,526	285,787
Other noncurrent liabilities	58,101	52,466
Total stockholders' equity	3,595,534	3,417,077
Total liabilities and stockholders' equity	4,397,167	4,113,835
Consolidation, Eliminations [Member]
Condensed Financial Information [Line Items]
Cash and cash equivalents	0	0	$ 0	$ 0
Trade accounts receivable, net	0	0
Inventories, net	0	0
Other current assets	0	0
Total current assets	0	0
Intercompany receivables, net	(1,751,125)	(1,771,921)
Property, buildings and equipment, net	0	0
Intangible assets, net	0	0
Goodwill and other intangibles, net	0	0
Investments in affiliates and other noncurrent assets	(6,016,787)	(5,631,472)
Total assets	(7,767,912)	(7,403,393)
Accounts payable	0	0
Other current liabilities	0	0
Total current liabilities	0	0
Intercompany payables, net	(1,751,125)	(1,771,921)
Long-term debt	0	0
Other noncurrent liabilities	0	0
Total stockholders' equity	(6,016,787)	(5,631,472)
Total liabilities and stockholders' equity	$ (7,767,912)	$ (7,403,393)

CONDENSED CONSOLIDATED INCOME STATEMENTS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Jun. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Condensed Financial Information [Line Items]
Net sales	$ 1,656,186	$ 1,580,376	$ 4,934,938	$ 4,536,196
Cost of goods sold	1,317,432	1,264,745	3,940,762	3,627,666
Selling, general and administrative expense	225,812	216,205	685,130	644,176
Depreciation and amortization	9,910	7,674	26,431	22,861
Results of affiliates' operations	0	0	0	0
Interest expense, net	12,654	15,079	33,093	41,651
Provision for income taxes	26,987	22,783	74,259	58,440
Net income	63,391	53,890	175,263	141,402
Net income attributable to noncontrolling interest	(24)	0	(4)	0
Net income attributable to WESCO International, Inc.	63,415	53,890	175,267	141,402
Comprehensive Income:
Foreign currency translation adjustment	10,652	(26,411)	14,297	(16,685)
Comprehensive income attributable to WESCO International, Inc.	74,067	27,479	189,564	124,717
Parent Company [Member]
Condensed Financial Information [Line Items]
Net sales	0	0	0	0
Cost of goods sold	0	0	0	0
Selling, general and administrative expense	25	18	49	62
Depreciation and amortization	0	0	0	0
Results of affiliates' operations	69,571	60,336	192,729	159,957
Interest expense, net	6,095	6,428	17,417	18,493
Provision for income taxes	0	0	0	0
Net income	63,451		175,263
Net income attributable to noncontrolling interest	0		0
Net income attributable to WESCO International, Inc.	63,451	53,890	175,263	141,402
Comprehensive Income:
Foreign currency translation adjustment	10,652	(26,411)	14,297	(16,685)
Comprehensive income attributable to WESCO International, Inc.	74,103	27,479	189,560	124,717
Guarantor Subsidiaries [Member]
Condensed Financial Information [Line Items]
Net sales	868,289	847,745	2,602,688	2,386,968
Cost of goods sold	689,522	680,897	2,074,165	1,913,902
Selling, general and administrative expense	121,006	134,671	413,540	404,112
Depreciation and amortization	3,980	2,780	11,231	8,228
Results of affiliates' operations	44,115	53,846	164,338	156,191
Interest expense, net	3,706	5,573	7,667	12,839
Provision for income taxes	24,679	17,334	67,694	44,121
Net income	69,511		192,729
Net income attributable to noncontrolling interest	0		0
Net income attributable to WESCO International, Inc.	69,511	60,336	192,729	159,957
Comprehensive Income:
Foreign currency translation adjustment	10,652	(26,411)	14,297	(16,685)
Comprehensive income attributable to WESCO International, Inc.	80,163	33,925	207,026	143,272
Non-Guarantor Subsidiaries [Member]
Condensed Financial Information [Line Items]
Net sales	816,211	764,880	2,432,239	2,223,588
Cost of goods sold	656,224	616,097	1,966,586	1,788,124
Selling, general and administrative expense	104,781	81,516	271,541	240,002
Depreciation and amortization	5,930	4,894	15,200	14,633
Results of affiliates' operations	0	0	0	0
Interest expense, net	2,853	3,078	8,009	10,319
Provision for income taxes	2,308	5,449	6,565	14,319
Net income	44,115		164,338
Net income attributable to noncontrolling interest	(24)		(4)
Net income attributable to WESCO International, Inc.	44,139	53,846	164,342	156,191
Comprehensive Income:
Foreign currency translation adjustment	10,652	(26,411)	14,297	(16,685)
Comprehensive income attributable to WESCO International, Inc.	54,791	27,435	178,639	139,506
Consolidation, Eliminations [Member]
Condensed Financial Information [Line Items]
Net sales	(28,314)	(32,249)	(99,989)	(74,360)
Cost of goods sold	(28,314)	(32,249)	(99,989)	(74,360)
Selling, general and administrative expense	0	0	0	0
Depreciation and amortization	0	0	0	0
Results of affiliates' operations	(113,686)	(114,182)	(357,067)	(316,148)
Interest expense, net	0	0	0	0
Provision for income taxes	0	0	0	0
Net income	(113,686)		(357,067)
Net income attributable to noncontrolling interest	0		0
Net income attributable to WESCO International, Inc.	(113,686)	(114,182)	(357,067)	(316,148)
Comprehensive Income:
Foreign currency translation adjustment	(21,304)	52,822	(28,594)	33,370
Comprehensive income attributable to WESCO International, Inc.	$ (134,990)	$ (61,360)	$ (385,661)	$ (282,778)

CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS (Details) - USD ($)	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Condensed Financial Information [Line Items]
Net cash (used) provided by operating activities	$ 189,683,000	$ 71,828,000
Investing Activities:
Capital expenditures	(19,469,000)	(23,966,000)
Acquisition payments	(201,123,000)	(8,166,000)
Other	51,000	86,000
Net cash used in investing activities	(220,541,000)	(32,046,000)
Financing Activities:
Net borrowings (repayments)	66,805,000	(1,029,000)
Equity transactions	(2,469,000)	(2,517,000)
Other	10,055,000	8,751,000
Net cash (used in) provided by financing activities	74,391,000	5,205,000
Effect of exchange rate changes on cash and cash equivalents	235,000	(4,515,000)
Net change in cash and cash equivalents	43,768,000	40,472,000
Cash and cash equivalents at the beginning of the period	63,869,000	53,577,000
Cash and cash equivalents at the end of the period	107,637,000
Parent Company [Member]
Condensed Financial Information [Line Items]
Net cash (used) provided by operating activities	(8,490,000)	(2,450,000)
Investing Activities:
Capital expenditures	0	0
Acquisition payments	0	0
Other	0	0
Net cash used in investing activities	0	0
Financing Activities:
Net borrowings (repayments)	10,957,000	4,973,000
Equity transactions	(2,469,000)	(2,517,000)
Other	0	0
Net cash (used in) provided by financing activities	8,488,000	2,456,000
Effect of exchange rate changes on cash and cash equivalents	0	0
Net change in cash and cash equivalents	(2,400)	6,000
Cash and cash equivalents at the beginning of the period	5,000	1,000
Cash and cash equivalents at the end of the period	3,000
Guarantor Subsidiaries [Member]
Condensed Financial Information [Line Items]
Net cash (used) provided by operating activities	201,343,000	33,256,000
Investing Activities:
Capital expenditures	(15,654,000)	(21,700,000)
Acquisition payments	(201,123,000)	(8,166,000)
Other	51,000	86,000
Net cash used in investing activities	(216,726,000)	(29,780,000)
Financing Activities:
Net borrowings (repayments)	36,589,000	(6,002,000)
Equity transactions	0	0
Other	10,055,000	8,751,000
Net cash (used in) provided by financing activities	46,644,000	2,749,000
Effect of exchange rate changes on cash and cash equivalents	0	0
Net change in cash and cash equivalents	31,261,000	6,225,000
Cash and cash equivalents at the beginning of the period	44,412,000	32,342,000
Cash and cash equivalents at the end of the period	75,673,000
Non-Guarantor Subsidiaries [Member]
Condensed Financial Information [Line Items]
Net cash (used) provided by operating activities	(3,170,000)	41,022,000
Investing Activities:
Capital expenditures	(3,815,000)	(2,266,000)
Acquisition payments	0	0
Other	0	0
Net cash used in investing activities	(3,815,000)	(2,266,000)
Financing Activities:
Net borrowings (repayments)	19,259,000	0
Equity transactions	0	0
Other	0	0
Net cash (used in) provided by financing activities	19,259,000	0
Effect of exchange rate changes on cash and cash equivalents	235,000	(4,515,000)
Net change in cash and cash equivalents	12,509,000	34,241,000
Cash and cash equivalents at the beginning of the period	19,452,000	21,234,000
Cash and cash equivalents at the end of the period	31,961,000
Consolidation, Eliminations [Member]
Condensed Financial Information [Line Items]
Net cash (used) provided by operating activities	0	0
Investing Activities:
Capital expenditures	0	0
Acquisition payments	0	0
Other	0	0
Net cash used in investing activities	0	0
Financing Activities:
Net borrowings (repayments)	0	0
Equity transactions	0	0
Other	0	0
Net cash (used in) provided by financing activities	0	0
Effect of exchange rate changes on cash and cash equivalents	0	0
Net change in cash and cash equivalents	0	0
Cash and cash equivalents at the beginning of the period	0	$ 0
Cash and cash equivalents at the end of the period	$ 0

SUBSEQUENT EVENTS (Details) - Acquisition [Member] - Eeecol Electric Corporation [Member] customers in Thousands, $ in Millions, $ in Billions		9 Months Ended
	Oct. 15, 2012 CAD ($) customers location	Sep. 30, 2012 USD ($)
Subsequent Event [Line Items]
Business Acquisition, Effective Date of Acquisition	10/15/2012
Business Acquisition, Cost of Acquired Entity, Purchase Price \| $	$ 1,140
Business Acquisition, Revenue Reported by Acquired Entity for Last Annual Period \| $		$ 0.9
Business Acquisition, Number of Customers Acquired \| customers	20
CANADA
Subsequent Event [Line Items]
Business Acquisition, Number of Locations Acquired \| location	57
South America [Member]
Subsequent Event [Line Items]
Business Acquisition, Number of Locations Acquired \| location	20