Jointly Owned Facilities (Tables)

12 Months Ended

Dec. 31, 2023

Regulated Operations [Abstract]

Schedule of Jointly Owned Utility Plants

At December 31, the Company's share of the cost of utility plant in service, construction work in progress and related accumulated depreciation for the jointly owned facilities was as follows:

	Ownership Percentage		2023		2022
			(In thousands)
Big Stone Station:	22.7	%
Utility plant in service			$	159,437	$	157,699
Construction work in progress			197		231
Less accumulated depreciation			52,264		48,590
			$	107,370	$	109,340
BSSE:	50.0	%
Utility plant in service			$	107,260	$	107,260
Construction work in progress			—		—
Less accumulated depreciation			8,111		6,182
			$	99,149	$	101,078
Coyote Station:	25.0	%
Utility plant in service			$	160,208	$	158,274
Construction work in progress			159		1,807
Less accumulated depreciation			113,187		111,203
			$	47,180	$	48,878
JETx:	50.0	%
Utility plant in service			$	—	$	—
Construction work in progress			1,372		—
Less accumulated depreciation			—		—
			$	1,372	$	—
Wygen III:	25.0	%
Utility plant in service			$	66,852	$	66,238
Construction work in progress			127		273
Less accumulated depreciation			13,728		12,477
			$	53,251	$	54,034