Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Deferred tax liabilities
Investments	$ 0	$ 0
Derivative contracts	0	0
Total deferred tax liabilities	0	0
Deferred tax assets
Property, plant and equipment	57,061	68,750
Net operating loss carryforwards	373,506	372,903
Tax credits and other carryforwards	33,851	33,851
Asset retirement obligations	13,327	13,551
Investments	97	121
Other	1,454	1,618
Total deferred tax assets	479,296	490,794
Valuation allowance	(406,495)	(440,225)
Net deferred tax asset	$ 72,801	$ 50,569