Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Gross Sales	$ 1,644,976	$ 1,537,869
Cash discounts	(7,324)	(7,298)
Net Sales	1,637,652	1,530,571
Cost of merchandise sold	(1,326,233)	(1,230,742)
Gross Margin	311,419	299,829
Selling, general and administrative expenses	(263,361)	(252,995)
Depreciation and amortization	(12,057)	(11,876)
Other income, net	764	608
Income from Operations	36,765	35,566
Non-operating expenses	(7,486)	(5,847)
Income before Provision for Income Taxes	29,279	29,719
Provision for income taxes	(8,115)	(11,996)
Net Income	21,164	17,723
Less: Net income attributable to noncontrolling interests	(71)	(42)
Net Income attributable to Graybar Electric Company, Inc.	$ 21,093	$ 17,681
Net Income per share of Common Stock (in dollars per share)	$ 1.08	$ 0.91	[1]
Cash Dividends per share of Common Stock (in dollars per share)	$ 0.30	$ 0.30
Average Common Shares Outstanding (Shares)	19,545	19,383

[1] (A)Adjusted for the declaration of a 10% stock dividend in 2017, shares related to which were issued in February 2018. Prior to the adjustment, the average common shares outstanding were 17,621 for the three months ended March 31, 2017.