SCHEDULE OF EARNINGS PER SHARE, BASIC AND DILUTED (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share [Abstract]
Net income (loss) attributable to WESCO International, Inc.	$ 119,195	$ 59,178	$ (34,506)	$ 34,407	$ 178,373	$ (100)
Weighted average common shares outstanding used in computing basic earnings per share (in shares)	50,243,000		42,683,000		50,184,000	42,260,000
Common shares issuable upon exercise of dilutive stock options (in shares)	1,751,000		92,000		1,691,000	152,000
Weighted average common shares outstanding and common share equivalents used in computing diluted earnings per share (in shares)	51,994,000		42,775,000		51,875,000	42,412,000
Weighted Average Number of Shares Outstanding, Basic and Diluted			42,683,000			42,260,000
Earnings Per Share, Basic and Diluted [Abstract]
Basic (in dollars per share)	$ 2.09		$ (0.84)		$ 2.98	$ (0.03)
Diluted (in dollars per share)	$ 2.02		$ (0.84)		$ 2.89	$ (0.03)
Net Income (Loss) Available to Common Stockholders, Basic	$ 104,843		$ (35,782)		$ 149,669	$ (1,376)
Preferred Stock Dividends, Income Statement Impact	$ 14,352		$ 1,276		$ 28,704	$ 1,276