Balance Sheet Components (Tables)

9 Months Ended

Sep. 30, 2022

Balance Sheet Related Disclosures [Abstract]

Materials and Supplies, Fuel Stock and Stored Natural Gas

Inventories of materials and supplies, fuel stock and stored natural gas are recorded at average cost for our regulated operations and the lower of cost or net realizable value for our non-regulated operations and consisted of the following as of September 30, 2022 and December 31, 2021 (dollars in thousands):

	September 30,		December 31,
	2022		2021
Materials and supplies	$	70,763	$	62,003
Stored natural gas	$	47,039	$	17,604
Fuel stock		5,645		5,126
Total	$	123,447	$	84,733

Schedule of Other Current Assets

Other current assets consisted of the following as of September 30, 2022 and December 31, 2021 (dollars in thousands):

	September 30,		December 31,
	2022		2021
Prepayments		21,812		24,387
Income taxes receivable		23,620		29,615
Derivative assets net of collateral		5,022		1,398
Collateral posted for derivative instruments after netting with outstanding    derivatives	$	47,425	$	21,477
Other		3,414		3,877
Total	$	101,293	$	80,754

Net Utility Property

Schedule of Net Utility Property Recorded at Original Cost Net of Accumulated Depreciation

Net utility property, which is recorded at original cost net of accumulated depreciation, consisted of the following as of September 30, 2022 and December 31, 2021 (dollars in thousands):

	September 30,		December 31,
	2022		2021
Utility plant in service	$	7,453,971	$	7,166,580
Construction work in progress		167,139		205,405
Total		7,621,110		7,371,985
Less: Accumulated depreciation and amortization		2,242,266		2,146,470
Total	$	5,378,844	$	5,225,515

Other Property and Investments-Net and Other Non-Current Assets

Other property and investments-net and other non-current assets consisted of the following as of September 30, 2022 and December 31, 2021 (dollars in thousands):

	September 30,		December 31,
	2022		2021
Equity investments		113,390		91,057
Operating lease ROU assets		68,707		70,133
Finance lease ROU assets		40,966		43,697
Non-utility property		25,425		20,033
Notes receivable		17,254		14,949
Long-term prepaid license fees		15,710		8,465
Investment in affiliated trust		11,547		11,547
Derivative assets net of collateral		12,741		2,659
Deferred compensation assets		7,609		9,513
Other		11,038		8,490
Total	$	324,387	$	280,543

Other Current Liabilities

Other current liabilities consisted of the following as of September 30, 2022 and December 31, 2021 (dollars in thousands):

	September 30, 2022		December 31, 2021
Accrued taxes other than income taxes	$	40,579	$	41,706
Derivative liabilities		2,996		28,801
Employee paid time off accruals		29,638		27,741
Accrued interest		34,990		17,538
Deferred wholesale revenue		29,081		884
Pensions and other postretirement benefits		13,277		13,582
Other		42,412		38,609
Total	$	192,973	$	168,861

Schedule of Other Non-Current Liabilities and Deferred Credits

Other non-current liabilities and deferred credits consisted of the following as of September 30, 2022 and December 31, 2021 (dollars in thousands):

	September 30, 2022		December 31, 2021
Operating lease liabilities	$	67,702	$	66,068
Finance lease liabilities		43,304		45,730
Deferred investment tax credits		28,922		29,313
Asset retirement obligations		15,878		17,142
Derivative liabilities		4,673		4,525
Other		16,446		15,347
Total	$	176,925	$	178,125

Schedule of Regulatory Assets and Liabilities

Regulatory assets and liabilities consisted of the following as of September 30, 2022 and December 31, 2021 (dollars in thousands):

	September 30, 2022				December 31, 2021
	Current		Non-Current		Current		Non-Current
Regulatory Assets
Energy commodity derivatives	$	8,374	$	4,201	$	12,447	$	2,938
Decoupling surcharge		6,674		5,346		9,907		14,625
Deferred natural gas costs		38,674		—		14,095		6,932
Deferred power costs		4,413		—		7,334		3,501
Deferred income taxes		—		251,033		—		244,154
Pension and other postretirement benefit plans		—		161,665		—		165,696
Interest rate swaps		—		187,607		—		199,754
AFUDC above FERC allowed rate		—		50,956		—		48,455
Settlement with Coeur d'Alene Tribe		—		38,088		—		38,926
Advanced meter infrastructure		—		33,288		—		36,008
Utility plant abandoned		—		24,937		—		26,771
COVID-19 deferrals		—		13,497		—		13,591
Unamortized debt repurchase costs		—		6,305		—		6,768
Demand side management programs		—		5,144		—		3,974
Other regulatory assets		1,438		54,471		—		48,533
Total regulatory assets	$	59,573	$	836,538	$	43,783	$	860,626
Regulatory Liabilities
Income tax related liabilities	$	77,689	$	402,464	$	56,331	$	458,789
Deferred power costs		—		2,287		6,457		5,434
Decoupling rebate		7,504		17,748		3,049		6,259
Utility plant retirement costs		—		370,232		—		350,190
Interest rate swaps		—		23,556		—		15,062
COVID-19 deferrals		—		12,032		—		12,500
Other regulatory liabilities		12,888		17,176		11,312		13,281
Total regulatory liabilities	$	98,081	$	845,495	$	77,149	$	861,515