Regulatory Matters (Tables)

12 Months Ended

Dec. 31, 2023

Regulatory Assets and Liabilities Disclosure [Abstract]

Schedule of Regulatory Assets and Liabilities

The following presents our current and long-term regulatory assets and liabilities as of December 31, 2023 and 2022 and the period we expect to recover or refund such amounts:


	Period of	2023				2022
(in thousands)	Recovery/Refund	Current		Long-Term		Current		Long-Term

Regulatory Assets
Pension and Other Postretirement Benefit Plans1	See below	$	154	$	86,134	$	—	$	88,354
Alternative Revenue Program Riders2	Up to 2 years	3,719		158		5,679		2,508
Asset Retirement Obligations1	Asset lives	—		87		—		1,467
Deferred Income Taxes	Asset lives	—		6,940		—		—
Fuel Clause Adjustments1	Up to 1 year	7,294		—		10,893		—
Derivative Instruments1	Up to 1 year	4,210		—		7,130		—
Other1	Various	750		2,396		1,297		2,326
Total Regulatory Assets		16,127		95,715		24,999		94,655
Regulatory Liabilities
Deferred Income Taxes	Asset lives	—		136,022		—		131,480
Plant Removal Obligations	Asset lives	—		117,030		8,509		105,733
Fuel Clause Adjustments	Up to 1 year	11,350		—		365		—
Alternative Revenue Program Riders	Up to 1 year	6,885		—		2,504		—
North Dakota PTC Refunds	Asset lives	—		12,011		—		7,136
Pension and Other Postretirement Benefit Plans	See below	6,138		11,307		5,589		—



Other	Various	1,035		177		333		148
Total Regulatory Liabilities		$	25,408	$	276,547	$	17,300	$	244,497

1Costs subject to recovery without a rate of return.
2Amount eligible for recovery includes an incentive or rate of return.