Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Statement [Abstract]
Gross Sales		$ 1,697,037	$ 1,590,576	$ 4,806,245	$ 4,566,880
Cash discounts		(7,418)	(6,690)	(20,625)	(19,208)
Net Sales		1,689,619	1,583,886	4,785,620	4,547,672
Cost of merchandise sold		(1,370,861)	(1,280,928)	(3,881,616)	(3,692,343)
Gross Margin		318,758	302,958	904,004	855,329
Selling, general and administrative expenses		(254,969)	(244,672)	(750,266)	(717,648)
Depreciation and amortization		(12,283)	(10,960)	(35,158)	(32,082)
Other income, net		629	1,187	3,438	6,746
Income from Operations		52,135	48,513	122,018	112,345
Interest expense, net		(1,215)	(685)	(2,635)	(1,895)
Income before Provision for Income Taxes		50,920	47,828	119,383	110,450
Provision for income taxes		(20,724)	(19,431)	(48,396)	(44,414)
Net Income		30,196	28,397	70,987	66,036
Less: Net income attributable to noncontrolling interests		(67)	(86)	(178)	(177)
Net Income attributable to Graybar Electric Company, Inc.		$ 30,129	$ 28,311	$ 70,809	$ 65,859
Net Income per share of Common Stock (in dollars per share)	[1]	$ 1.82	$ 1.73	$ 4.28	$ 4.02
Cash Dividends per share of Common Stock (in dollars per share)		$ 0.30	$ 0.30	$ 0.90	$ 0.90
Average Common Shares Outstanding (Shares)	[1]	16,573	16,341	16,558	16,379

[1] (A)Adjusted for the declaration of a 2.5% stock dividend in 2015, shares related to which were issued in February 2016. Prior to the adjustment, the average common shares outstanding were 15,942 and 15,980 for the three and nine months ended September 30, 2015, respectively.