v3.26.1
Regulatory Matters (Tables)
 6 Months Ended
Jun. 30, 2026
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 June 30, 2026 and December 31, 2025 and the period we expect to recover or refund such amounts:
Period ofJune 30, 2026December 31, 2025
(in thousands)Recovery/RefundCurrentLong-TermCurrentLong-Term
Regulatory Assets
Pension and Other Postretirement Benefit Plans1
Various$2,765 $73,141 $2,765 $72,762 
Alternative Revenue Program Riders2
Up to 2 years
9,193 3,489 7,834 1,036 
Deferred Income Taxes1
Asset lives— 8,907 — 9,007 
Fuel Clause Adjustments1
Up to 1 year
4,528 — 6,558 — 
Derivative Instruments1
Up to 2 years
2,494 915 2,717 — 
Other1
Various937 5,391 563 3,257 
Total Regulatory Assets$19,917 $91,843 $20,437 $86,062 
Regulatory Liabilities
Deferred Income TaxesAsset lives$— $122,921 $— $125,413 
Plant Removal ObligationsAsset lives— 127,059 — 130,686 
Fuel Clause Adjustments
Up to 1 year
11,585 — 1,231 — 
Alternative Revenue Program Riders
Up to 1 year
11,469 — 9,961 — 
North Dakota PTC RefundsAsset lives— 38,123 — 29,169 
Pension and Other Postretirement Benefit PlansVarious3,174 10,109 3,174 9,187 
OtherVarious2,602 2,508 2,234 2,943 
Total Regulatory Liabilities$28,830 $300,720 $16,600 $297,398 
1Costs subject to recovery without a rate of return.
2Amounts eligible for recovery include an incentive or rate of return.