Revolving Credit Facility Credit Agreement (Details) (USD $) In Thousands, unless otherwise specified					6 Months Ended
	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2014 Original Credit Facility [Member]	Jun. 30, 2014 Revolving Credit Facility [Member]	Jun. 30, 2014 Line of Credit [Member] London Interbank Offered Rate (LIBOR) [Member]	Jun. 30, 2014 Line of Credit [Member] Base Rate [Member]	Jun. 30, 2014 Minimum [Member] London Interbank Offered Rate (LIBOR) [Member]	Jun. 30, 2014 Minimum [Member] Line of Credit [Member]	Jun. 30, 2014 Minimum [Member] Line of Credit [Member] Base Rate [Member]	Jun. 30, 2014 Minimum [Member] Letter of Credit [Member]	Jun. 30, 2014 Maximum [Member] London Interbank Offered Rate (LIBOR) [Member]	Jun. 30, 2014 Maximum [Member] Line of Credit [Member]	Jun. 30, 2014 Maximum [Member] Line of Credit [Member] Base Rate [Member]	Jun. 30, 2014 Maximum [Member] Letter of Credit [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity			$ 500,000	$ 550,000
Combined Letter of Credit Sub-Facility			50,000	50,000
US Swing Line Loan Facility			50,000	50,000
Canadian Swing Line Loan Facility			20,000	20,000
Sublimit for Borrowings by Graybar Canada			100,000	100,000
Aggregate Borrowing Commitments			200,000	300,000
Letters of Credit Outstanding, Amount	6,547	6,886
Letters of credit, outstanding under revolving credit facility	$ 372	$ 711
Line of Credit Facility, Commitment Fee Percentage								0.25%		1.00%		0.40%		1.60%
Debt Instrument, Description of Variable Rate Basis					LIBOR	base rate loans
Debt Instrument, Basis Spread on Variable Rate							1.00%		0.00%		1.60%		0.60%