SELECTED QUARTERLY FINANCIAL DATA (Tables)

12 Months Ended

Dec. 31, 2019

Quarterly Financial Information Disclosure [Abstract]

Schedule of Quarterly Financial Information

	First Quarter		Second Quarter		Third Quarter		Fourth Quarter
2019
Net Sales	$	1,961,267	$	2,150,088	$	2,148,110	$	2,099,452
Cost of goods sold (excluding depreciation and amortization)	1,578,771		1,741,114		1,747,913		1,709,658
Income from operations	70,726		97,950		93,733		83,808
Income before income taxes	53,606		80,643		80,225		67,587
Net income	41,950		63,215		64,339		52,694
Net income attributable to WESCO International	42,369		63,464		64,495		53,098
Basic earnings per share attributable to WESCO International(1)	0.94		1.46		1.53		1.27
Diluted earnings per share attributable to WESCO International(2)	0.93		1.45		1.52		1.26
2018
Net Sales	$	1,993,915	$	2,103,994	$	2,067,245	$	2,011,447
Cost of goods sold (excluding depreciation and amortization)	1,613,966		1,704,100		1,670,037		1,621,117
Income from operations	73,241		91,183		97,517		90,499
Income before income taxes	53,458		73,442		80,467		73,658
Net income	42,971		57,673		66,645		58,066
Net income attributable to WESCO International	44,421		57,940		66,849		58,133
Basic earnings per share attributable to WESCO International(1)	0.94		1.23		1.42		1.27
Diluted earnings per share attributable to WESCO International(2)	0.93		1.22		1.41		1.26