Debt (Narrative) (Details) - USD ($)		12 Months Ended
	Jul. 20, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jul. 19, 2023
Line of Credit Facility [Line Items]
Fixed rate debt carrying amount in excess of fair value		$ 200,000	$ 300,000
Short-term borrowings		0	31,600,000
Interest expense, net		2,600,000	1,600,000	$ 1,000,000.0
Debt instrument interest expense		2,700,000	2,000,000.0	$ 1,000,000.0
Minimum [Member]
Line of Credit Facility [Line Items]
Short-term borrowings		0	0
Maximum [Member]
Line of Credit Facility [Line Items]
Short-term borrowings		232,000,000.0	173,100,000
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Short-term borrowings		30,000,000.0
Letters of credit outstanding			1,900,000
Letter of Credit [Member]
Line of Credit Facility [Line Items]
Letters of credit outstanding		9,400,000	7,800,000
Amended Credit Agreement [Member]
Line of Credit Facility [Line Items]
Short-term debt average amount outstanding		62,100,000	65,700,000
Letters of credit outstanding		3,600,000
Unused borrowing capacity, amount		$ 746,400,000	$ 718,100,000
Amended Credit Agreement [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Credit agreement commitment fee percentage			0.25%
Amended Credit Agreement [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Credit agreement commitment fee percentage			0.40%
Amended Credit Agreement [Member] | Weighted Average [Member]
Line of Credit Facility [Line Items]
Interest rate during the period		6.09%	1.98%
Amended Credit Agreement [Member] | Bridge Loan [Member] | Line of credit [Member] | Graybar Canada [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity			$ 100,000,000.0
Amended Credit Agreement [Member] | Bridge Loan [Member] | United States [Member] | Line of credit [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity			75,000,000.0
Amended Credit Agreement [Member] | Bridge Loan [Member] | Canada [Member] | Line of credit [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity			$ 20,000,000.0
Amended Credit Agreement [Member] | Revolving Credit Facility [Member] | Minimum [Member] | Base Rate [Member]
Line of Credit Facility [Line Items]
Basis spread on variable rate			0.00%
Amended Credit Agreement [Member] | Revolving Credit Facility [Member] | Minimum [Member] | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]
Line of Credit Facility [Line Items]
Basis spread on variable rate			1.00%
Amended Credit Agreement [Member] | Revolving Credit Facility [Member] | Maximum [Member] | Base Rate [Member]
Line of Credit Facility [Line Items]
Basis spread on variable rate			0.60%
Amended Credit Agreement [Member] | Revolving Credit Facility [Member] | Maximum [Member] | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]
Line of Credit Facility [Line Items]
Basis spread on variable rate			1.60%
Amended Credit Agreement [Member] | Revolving Credit Facility [Member] | Line of credit [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity			$ 750,000,000.0
Accordion feature, increase limit			$ 375,000,000.0
Expiration date			Aug. 01, 2026
Debt instrument, term			5 years
Amended Credit Agreement [Member] | Letter of Credit [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Credit agreement commitment fee percentage			1.00%
Amended Credit Agreement [Member] | Letter of Credit [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Credit agreement commitment fee percentage			1.60%
Amended Credit Agreement [Member] | Letter of Credit Sub Facility [Member] | Line of credit [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity			$ 25,000,000.0
Prudential Private Placement Shelf Agreement [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 200,000,000.0				$ 100,000,000.0
Debt maturity date	Aug. 01, 2026
Issuance period		3 years
Loans Payable		$ 0	0
MetLife Private Placement Shelf Agreement [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity		150,000,000.0
Loans Payable		$ 0	$ 0