CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues	$ 8,358,917	$ 8,176,601	$ 7,679,021
Cost of goods sold (excluding depreciation and amortization below)	6,777,456	6,609,220	6,194,366
Selling, general and administrative expense	1,173,137	1,151,944	1,101,598
Depreciation and amortization	62,107	62,997	64,017
Revenue from Contract with Customer, Excluding Assessed Tax	8,358,917	8,176,601	7,679,021
Income from operations	346,217	352,440	319,040
Interest expense, net	64,156	71,415	66,600
Income before income taxes	282,061	281,025	252,440
Provision for income taxes	59,863	55,670	89,307
Net income	222,198	225,355	163,133
Net loss attributable to noncontrolling interest	(1,228)	(1,988)	(327)
Net Income attributable to WESCO International, Inc.	223,426	227,343	163,460
Comprehensive Income:
Foreign currency translation adjustment	49,306	(99,643)	85,762
Benefit plan adjustments	(8,643)	3,798	(6,381)
Comprehensive income attributable to WESCO International, Inc.	$ 264,089	$ 131,498	$ 242,841
Earnings per share :
Basic	$ 5.18	$ 4.87	$ 3.42
Diluted	$ 5.14	$ 4.82	$ 3.38
Shipping and Handling [Member]
Cost of goods sold (excluding depreciation and amortization below)	$ 71,700	$ 74,100	$ 61,800