CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Condensed Financial Information [Line Items]
Payments for (Proceeds from) Other Investing Activities	$ (785)	$ (39)
Net cash (used) provided by operating activities	90,056	46,713
Investing Activities:
Capital expenditures	(5,026)	(5,012)
Acquisition payments	0	(91,187)
Net cash used in investing activities	(4,241)	(96,160)
Financing Activities:
Borrowings	369,299us-gaap_ProceedsFromIssuanceOfDebt	423,425us-gaap_ProceedsFromIssuanceOfDebt
Repayments	(388,279)us-gaap_RepaymentsOfDebt	(403,443)us-gaap_RepaymentsOfDebt
Payments for Repurchase of Common Stock	(27,602)	(5,331)
Proceeds from (Payments for) Other Financing Activities	(7,209)	8,888
Net cash used in financing activities	(53,791)	23,539
Effect of exchange rate changes on cash and cash equivalents	(5,992)	(1,461)
Net change in cash and cash equivalents	26,032	(27,369)
Cash and cash equivalents at the beginning of period	128,319	123,725
Cash and cash equivalents at the end of period	154,351	96,356
Parent Company [Member]
Condensed Financial Information [Line Items]
Payments for (Proceeds from) Other Investing Activities	0	0
Net cash (used) provided by operating activities	(4,441)	(4,871)
Investing Activities:
Capital expenditures	0	0
Acquisition payments		0
Net cash used in investing activities	0	0
Financing Activities:
Borrowings	32,125	5,168
Repayments	0	0
Payments for Repurchase of Common Stock	(27,602)	(5,331)
Proceeds from (Payments for) Other Financing Activities	(82)	5,034
Net cash used in financing activities	4,441	4,871
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 period	0	0
Cash and cash equivalents at the end of period	0	0
WESCO Distribution, Inc.
Condensed Financial Information [Line Items]
Payments for (Proceeds from) Other Investing Activities	32,125	5,169
Net cash (used) provided by operating activities	53,333	20,415
Investing Activities:
Capital expenditures	(4,005)	(3,347)
Acquisition payments		0
Net cash used in investing activities	(36,130)	(8,516)
Financing Activities:
Borrowings	218,699	307,851
Repayments	(221,699)	(307,851)
Payments for Repurchase of Common Stock	0	0
Proceeds from (Payments for) Other Financing Activities	(7,127)	3,858
Net cash used in financing activities	(10,127)	3,858
Effect of exchange rate changes on cash and cash equivalents	0	0
Net change in cash and cash equivalents	7,076	15,757
Cash and cash equivalents at the beginning of period	32,508	31,695
Cash and cash equivalents at the end of period	39,584	47,452
Non-Guarantor Subsidiaries [Member]
Condensed Financial Information [Line Items]
Payments for (Proceeds from) Other Investing Activities	(785)	(39)
Net cash (used) provided by operating activities	41,164	31,169
Investing Activities:
Capital expenditures	(1,021)	(1,665)
Acquisition payments		(91,187)
Net cash used in investing activities	(236)	(92,813)
Financing Activities:
Borrowings	150,600	115,575
Repayments	(166,580)	(95,592)
Payments for Repurchase of Common Stock	0	0
Proceeds from (Payments for) Other Financing Activities	0	(4)
Net cash used in financing activities	(15,980)	19,979
Effect of exchange rate changes on cash and cash equivalents	(5,992)	(1,461)
Net change in cash and cash equivalents	18,956	(43,126)
Cash and cash equivalents at the beginning of period	95,811	92,030
Cash and cash equivalents at the end of period	114,767	48,904
Consolidation, Eliminations [Member]
Condensed Financial Information [Line Items]
Payments for (Proceeds from) Other Investing Activities	(32,125)	(5,169)
Net cash (used) provided by operating activities	0	0
Investing Activities:
Capital expenditures	0	0
Acquisition payments		0
Net cash used in investing activities	32,125	5,169
Financing Activities:
Borrowings	(32,125)	(5,169)
Repayments	0	0
Payments for Repurchase of Common Stock	0	0
Proceeds from (Payments for) Other Financing Activities	0	0
Net cash used in financing activities	(32,125)	(5,169)
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 period	0	0
Cash and cash equivalents at the end of period	0	0
Consolidated Entities [Member]
Financing Activities:
Payments for Repurchase of Common Stock	$ (27,602)

Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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