Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016		Jun. 30, 2017		Jun. 30, 2016
Income Statement [Abstract]
Gross Sales	$ 1,720,842	$ 1,637,514		$ 3,258,711		$ 3,109,208
Cash discounts	(7,962)	(6,993)		(15,260)		(13,207)
Net Sales	1,712,880	1,630,521		3,243,451		3,096,001
Cost of merchandise sold	(1,389,987)	(1,324,922)		(2,620,729)		(2,510,755)
Gross Margin	322,893	305,599		622,722		585,246
Selling, general and administrative expenses	(257,338)	(250,565)		(515,383)		(495,297)
Depreciation and amortization	(12,144)	(11,564)		(24,020)		(22,875)
Other income, net	3,521	517		4,129		2,809
Income from Operations	56,932	43,987		87,448		69,883
Interest expense, net	(1,068)	(763)		(1,865)		(1,420)
Income before Provision for Income Taxes	55,864	43,224		85,583		68,463
Provision for income taxes	(22,463)	(17,530)		(34,459)		(27,672)
Net Income	33,401	25,694		51,124		40,791
Less: Net income attributable to noncontrolling interests	(67)	(59)		(109)		(111)
Net Income attributable to Graybar Electric Company, Inc.	$ 33,334	$ 25,635		$ 51,015		$ 40,680
Net Income per share of Common Stock (in dollars per share)	$ 1.89	$ 1.47	[1]	$ 2.89	[1]	$ 2.34	[1]
Cash Dividends per share of Common Stock (in dollars per share)	$ 0.30	$ 0.30		$ 0.60		$ 0.60
Average Common Shares Outstanding (Shares)	17,642	17,397		17,631		17,383

[1] (A)Adjusted for the declaration of a 5% stock dividend in 2016, shares related to which were issued in February 2017. Prior to the adjustment, the average common shares outstanding were 16,569 and 16,555 for the three and six months ended June 30, 2016, respectively.