Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net Income	$ 71,935	$ 93,313	$ 91,332
Other Comprehensive Income
Foreign currency translation	5,945	2,218	(13,240)
Pension and postretirement benefits liability adjustment (net of tax of $10,047, $5,245, and $16,261, respectively)	(15,780)	(8,238)	(25,542)
Total Other Comprehensive Loss	(9,835)	(6,020)	(38,782)
Comprehensive Income	62,100	87,293	52,550
Less: comprehensive income (loss) attributable to noncontrolling interests, net of tax	531	379	(276)
Comprehensive Income attributable to Graybar Electric Company, Inc.	$ 61,569	$ 86,914	$ 52,826