Income Taxes - Net Deferred Tax Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Deferred tax assets (DTAs):
Net operating loss and tax credit carryforwards	$ 99,327	$ 97,655
Unrealized mark-to-market, impairments and loss provisions	13,649	12,609
Other realized / unrealized treatment differences	(28,061)	(28,620)
Total deferred tax assets	84,915	81,644
Less: valuation allowance	(84,915)	(81,644)
Net deferred tax assets	$ 0	$ 0