Debt (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Line of Credit Facility [Line Items]
Fixed rate debt carrying amount in excess of fair value	$ 100,000	$ 200,000
Short-term borrowings	22,000,000.0
Interest expense, net	900,000	2,600,000	$ 1,600,000
Debt instrument interest expense		2,700,000	2,000,000.0
Minimum [Member]
Line of Credit Facility [Line Items]
Short-term borrowings	0	0
Maximum [Member]
Line of Credit Facility [Line Items]
Short-term borrowings	55,000,000.0	232,000,000.0
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Letters of credit outstanding		3,600,000
Letter of Credit [Member]
Line of Credit Facility [Line Items]
Letters of credit outstanding	9,600,000	9,400,000
Amended Credit Agreement [Member]
Line of Credit Facility [Line Items]
Short-term debt average amount outstanding	2,800,000	62,100,000
Letters of credit outstanding	3,800,000
Unused borrowing capacity, amount	$ 724,200,000	$ 746,400,000
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	6.28%	6.09%
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]
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]
Loans Payable		$ 0	$ 0