Previously Issued Condensed Consolidated Financial Statements (Unaudited) - Narrative (Details) - USD ($) $ in Thousands			3 Months Ended		6 Months Ended	9 Months Ended	12 Months Ended
	Aug. 11, 2025	May 22, 2025	Sep. 30, 2025	Jun. 30, 2025	Jun. 30, 2025	Sep. 30, 2025	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Income tax expense				$ 79,865	$ 107,534		$ 96,037	$ 33,157	$ 29,410
Deferred income tax liabilities, net							977,312	857,982
Current maturities of long-term debt			$ 75,000			$ 75,000	75,000	0
Long-term debt, less current maturities			3,432,120			3,432,120	$ 3,433,012	$ 3,504,477
Continuing Operations
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Income tax expense			7,039			71,172
Adjustments
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Income tax expense				27,271	27,271
Deferred income tax liabilities, net			35,100	$ 27,300	$ 27,300	35,100
Current maturities of long-term debt			75,000			75,000
Long-term debt, less current maturities			(75,000)			(75,000)
Adjustments \| Continuing Operations
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Income tax expense			$ 7,842			$ 35,113
Public Offering And Private Placement
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Sale of stock, number of shares (in shares)	18,823,500	13,207,142

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References

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+ Details

Southwest Gas Holdings, Inc. 10-K