Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net Income	$ 53,672	$ 29,554	$ 119,417	$ 80,678
Other Comprehensive Income
Foreign currency translation	1,759	3,616	(2,533)	6,550
Pension and postretirement benefits liability adjustment (net of tax of $(1,654), $(1,997), $(4,964), and $(5,990), respectively)	4,773	3,136	14,317	9,408
Total Other Comprehensive Income	6,532	6,752	11,784	15,958
Comprehensive Income	60,204	36,306	131,201	96,636
Less: comprehensive income attributable to noncontrolling interests, net of tax	174	209	193	457
Comprehensive Income attributable to Graybar Electric Company, Inc.	$ 60,030	$ 36,097	$ 131,008	$ 96,179