Utility Plant and Leases (Tables)

12 Months Ended

Dec. 31, 2018

Regulated Operations [Abstract]

Schedule of Net Utility Plant

Net utility plant as of December 31, 2018 and 2017 was as follows (thousands of dollars):

December 31,	2018			2017
Gas plant:
Storage	$	26,825		$	25,019
Transmission	386,159			363,396
Distribution	6,049,380			5,600,769
General	416,643			396,252
Software and software-related intangibles	241,158			230,030
Other	14,074			14,178
	7,134,239			6,629,644
Less: accumulated depreciation and amortization	(2,234,029		)	(2,231,242		)
Construction work in progress	193,028			125,248
Net utility plant	$	5,093,238		$	4,523,650

Schedule of Depreciation and Amortization Expense

Depreciation and amortization expense on gas plant, including intangibles, was as follows (thousands of dollars):

	2018		2017		2016
Depreciation and amortization expense	$	185,719	$	187,075	$	214,037

Schedule of Rental Payments for Operating Leases

The table below presents Southwest’s and Centuri’s rental and lease payments that are included in operating expenses (in thousands):

	2018		2017		2016
Southwest Gas Corporation	$	4,556	$	4,926	$	4,357
Centuri	59,491		62,310		53,956
Consolidated rental payments/lease expense	$	64,047	$	67,236	$	58,313

Schedule of Future Minimum Lease Payments for Operating Leases

The following is a schedule of future minimum lease payments for operating leases (with initial or remaining terms in excess of one year) as of December 31, 2018 (thousands of dollars):

	Southwest		Centuri		Consolidated Total
2019	$	898	$	10,053	$	10,951
2020	363		7,656		8,019
2021	299		5,760		6,059
2022	163		5,163		5,326
2023	79		3,681		3,760
Thereafter	177		10,511		10,688
Total minimum lease payments	$	1,979	$	42,824	$	44,803