CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Total	Common stock shares	Additional paid-in capital	Accumulated other comprehensive loss	Retained earnings	Southwest Gas Holdings, Inc.
Beginning balance (in shares) at Dec. 31, 2020		57,193,000
Beginning balance at Dec. 31, 2020		$ 58,823	$ 1,609,155	$ (61,003)	$ 1,067,978
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issuances (in shares)		3,229,000
Common stock issuances		$ 3,229	219,298
Promissory notes in association with redeemable noncontrolling interest			(4,237)
Foreign currency exchange translation adjustment				20
Net actuarial gain (loss) arising during period, less amortization of unamortized benefit plan cost, net of tax				12,570
FSIRS amounts reclassified to net income, net of tax	$ 1,652			1,652
Net income (loss)					200,779
Redemption value adjustments					(12,016)
Dividends declared					(142,428)
Ending balance (in shares) at Dec. 31, 2021		60,422,000
Ending balance at Dec. 31, 2021		$ 62,052	1,824,216	(46,761)	1,114,313	$ 2,953,820
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per common share (in USD per share)	$ 2.38
Common stock issuances (in shares)		6,697,000
Common stock issuances		$ 6,697	462,967
Promissory notes in association with redeemable noncontrolling interest			0
Foreign currency exchange translation adjustment				(6,133)
Net actuarial gain (loss) arising during period, less amortization of unamortized benefit plan cost, net of tax				8,236
FSIRS amounts reclassified to net income, net of tax	$ 416			416
Net income (loss)					(203,290)
Redemption value adjustments	$ (3,325)				3,325
Dividends declared					(167,279)
Ending balance (in shares) at Dec. 31, 2022	67,119,143	67,119,000
Ending balance at Dec. 31, 2022		$ 68,749	2,287,183	(44,242)	747,069	3,058,759
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per common share (in USD per share)	$ 2.48
Common stock issuances (in shares)		4,445,000
Common stock issuances		$ 4,445	254,557
Promissory notes in association with redeemable noncontrolling interest			50
Foreign currency exchange translation adjustment				2,742
Net actuarial gain (loss) arising during period, less amortization of unamortized benefit plan cost, net of tax				(2,287)
FSIRS amounts reclassified to net income, net of tax	$ 0			0
Net income (loss)					150,889
Redemption value adjustments	$ (19,366)				19,366
Dividends declared					(178,485)
Ending balance (in shares) at Dec. 31, 2023	71,563,750	71,564,000
Ending balance at Dec. 31, 2023		$ 73,194	$ 2,541,790	$ (43,787)	$ 738,839	$ 3,310,036
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per common share (in USD per share)	$ 2.48