Commitments and Contingencies (Details) $ in Thousands	Sep. 30, 2022 USD ($)
Subsidiaries [Member]
Loss Contingencies [Line Items]
Contractual Obligation	$ 466,600
Colstrip Units 1 and 2 [Member] | Colstrip Units 1 and 2 [Member]
Loss Contingencies [Line Items]
Ownership interest (percent)	50.00%
Colstrip Units 3 and 4 [Member] | Colstrip Units 3 and 4 [Member]
Loss Contingencies [Line Items]
Ownership interest (percent)	25.00%