Regulatory Matters (Tables)

9 Months Ended

Sep. 30, 2025

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 September 30, 2025 and December 31, 2024 and the period we expect to recover or refund such amounts:


	Period of	September 30, 2025				December 31, 2024
(in thousands)	Recovery/Refund	Current		Long-Term		Current		Long-Term

Regulatory Assets
Pension and Other Postretirement Benefit Plans1	Various	$	—	$	87,182	$	—	$	88,161
Alternative Revenue Program Riders2	Up to 2 years	4,610		146		4,257		195
Deferred Income Taxes1	Asset lives	—		9,070		—		8,944
Fuel Clause Adjustments1	Up to 1 year	3,229		—		2,218		—
Derivative Instruments1	Up to 2 years	795		512		1,989		—
Other1	Various	799		1,026		1,498		1,373
Total Regulatory Assets		$	9,433	$	97,936	$	9,962	$	98,673
Regulatory Liabilities
Deferred Income Taxes	Asset lives	$	—	$	124,832	$	—	$	130,387
Plant Removal Obligations	Asset lives	—		132,438		—		126,263
Fuel Clause Adjustments	Up to 1 year	5,197		—		11,432		—
Alternative Revenue Program Riders	Up to 1 year	10,888		—		14,255		—
North Dakota PTC Refunds	Asset lives	—		26,348		—		20,099
Pension and Other Postretirement Benefit Plans	Various	2,547		10,350		2,547		10,758



Other	Various	3,121		2,248		1,073		1,421
Total Regulatory Liabilities		$	21,753	$	296,216	$	29,307	$	288,928

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