Debt (Tables)

3 Months Ended

Mar. 31, 2022

Debt Disclosure [Abstract]

Schedule of Carrying Amounts and Estimated Fair Values of Long-Term Debt

	March 31, 2022				December 31, 2021
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
(Thousands of dollars)
Southwest Gas Corporation:
Debentures:
Notes, 6.1%, due 2041	$	125,000	$	146,293	$	125,000	$	166,380
Notes, 4.05%, due 2032	600,000		598,242		—		—
Notes, 3.875%, due 2022	250,000		249,993		250,000		250,603
Notes, 4.875%, due 2043	250,000		272,933		250,000		307,538
Notes, 3.8%, due 2046	300,000		276,144		300,000		329,055
Notes, 3.7%, due 2028	300,000		303,660		300,000		325,191
Notes, 4.15%, due 2049	300,000		296,361		300,000		342,030
Notes, 2.2%, due 2030	450,000		398,066		450,000		440,838
Notes, 3.18%, due 2051	300,000		246,813		300,000		292,116
8% Series, due 2026	75,000		86,880		75,000		92,623
Medium-term notes, 7.78% series, due 2022	—		—		25,000		25,122
Medium-term notes, 7.92% series, due 2027	25,000		28,987		25,000		31,555
Medium-term notes, 6.76% series, due 2027	7,500		8,230		7,500		8,949
Unamortized discount and debt issuance costs	(27,091)				(19,959)
	2,955,409				2,387,541
Revolving credit facility and commercial paper	—		—		130,000		130,000
Industrial development revenue bonds:
Tax-exempt Series A, due 2028	50,000		50,000		50,000		50,000
2003 Series A, due 2038	50,000		50,000		50,000		50,000
2008 Series A, due 2038	50,000		50,000		50,000		50,000
2009 Series A, due 2039	50,000		50,000		50,000		50,000
Unamortized discount and debt issuance costs	(1,853)				(1,938)
	198,147				198,062
Less: current maturities	(250,000)				(275,000)
Southwest Gas Corporation total long-term debt, less current maturities	$	2,903,556			$	2,440,603
Southwest Gas Holdings, Inc.:
Centuri secured term loan facility	$	1,014,275	$	1,000,329	$	1,117,138	$	1,117,841
Centuri secured revolving credit facility	108,035		108,060		103,329		103,749
MountainWest unsecured senior notes, 3.53%, due in 2028	102,001		95,819		102,078		102,078
MountainWest unsecured senior notes, 4.875%, due in 2041	199,765		176,488		199,926		199,926
MountainWest unsecured senior notes, 3.91%, due in 2038	147,760		131,379		147,735		147,735
Other debt obligations	148,981		142,712		51,665		50,003
Unamortized discount and debt issuance costs	(23,546)				(24,466)
Less: current maturities	(41,069)				(22,324)
Southwest Gas Holdings, Inc. total long-term debt, less current maturities	$	4,559,758			$	4,115,684