REVENUE (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Net sales	[1]	$ 18,217,512	$ 12,325,995	$ 8,358,917
Selling, general and administrative expense		2,791,641	1,859,028	1,173,137
Contract with Customer, Asset, before Allowance for Credit Loss		33,400	19,400
Deferred Revenue		35,500	24,300
EES
Disaggregation of Revenue [Line Items]
Net sales		7,621,263	5,479,760	4,860,541
CSS
Disaggregation of Revenue [Line Items]
Net sales		5,715,238	3,323,264	909,496
UBS
Disaggregation of Revenue [Line Items]
Net sales		4,881,011	3,522,971	2,588,880
UNITED STATES
Disaggregation of Revenue [Line Items]
Net sales		13,157,866	9,110,453	6,234,119
Canada
Disaggregation of Revenue [Line Items]
Net sales		2,747,187	1,892,321	1,647,066
Other International
Disaggregation of Revenue [Line Items]
Net sales	[2]	2,312,459	1,323,221	477,732
Shipping and Handling [Member]
Disaggregation of Revenue [Line Items]
Selling, general and administrative expense		$ 248,300	$ 149,300	$ 71,700

[1] (2)    Wesco attributes revenues from external customers to individual countries on the basis of point of sale.

[2] (1)    No individual country's net sales are greater than 10% of total net sales.