Debt (Tables)

9 Months Ended

Sep. 30, 2020

Debt Disclosure [Abstract]

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

The Centuri secured revolving credit and term loan facility and Centuri’s other debt obligations (not actively traded) are categorized as Level 3. Because Centuri’s debt is not publicly traded, fair values for its secured revolving credit and term loan facility and other debt obligations were based on a conventional discounted cash flow methodology utilizing current market pricing yield curves, across Centuri’s debt maturity spectrum, of other industrial bonds with an assumed credit rating comparable to the Company’s.

	September 30, 2020				December 31, 2019
	Carrying Amount		Market Value		Carrying Amount		Market Value
(Thousands of dollars)
Southwest Gas Corporation:
Debentures:
Notes, 4.45%, due 2020	$	—	$	—	$	125,000	$	126,673
Notes, 6.1%, due 2041	125,000		172,353		125,000		162,666
Notes, 3.875%, due 2022	250,000		260,388		250,000		258,550
Notes, 4.875%, due 2043	250,000		317,325		250,000		291,928
Notes, 3.8%, due 2046	300,000		335,970		300,000		308,307
Notes, 3.7%, due 2028	300,000		341,388		300,000		320,685
Notes, 4.15%, due 2049	300,000		361,053		300,000		330,138
Notes, 2.2%, due 2030	450,000		471,227		—		—
8% Series, due 2026	75,000		99,423		75,000		96,905
Medium-term notes, 7.78% series, due 2022	25,000		26,944		25,000		27,500
Medium-term notes, 7.92% series, due 2027	25,000		33,716		25,000		32,543
Medium-term notes, 6.76% series, due 2027	7,500		9,569		7,500		9,156
Unamortized discount and debt issuance costs	(18,091)				(14,450)
	2,089,409				1,768,050
Revolving credit facility and commercial paper	58,000		58,000		150,000		150,000
Industrial development revenue bonds:
Variable-rate 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	(1,533)				(1,717)
	198,467				198,283
Less: current maturities	—				(125,000)
Long-term debt, less current maturities - Southwest Gas Corporation	$	2,345,876			$	1,991,333
Centuri:
Centuri term loan facility	$	231,010	$	236,477	$	244,812	$	252,182
Unamortized debt issuance costs	(890)				(1,101)
	230,120				243,711
Centuri secured revolving credit facility	59,908		59,950		60,021		60,057
Centuri other debt obligations	94,721		97,120		43,929		44,787
Less: current maturities	(44,903)				(38,512)
Long-term debt, less current maturities - Centuri	$	339,846			$	309,149
Consolidated Southwest Gas Holdings, Inc.:
Southwest Gas Corporation long-term debt	$	2,345,876			$	2,116,333
Centuri long-term debt	384,749				347,661
Less: current maturities	(44,903)				(163,512)
Long-term debt, less current maturities - Southwest Gas Holdings, Inc.	$	2,685,722			$	2,300,482