Income Taxes (Components of Deferred Tax Assets and Liabilities) (Details 2) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets
Loss and tax credit carryforwards - state	$ 54,943	$ 55,979
Derivative contracts	30,892	13,090
Accrued liabilities and other reserves	19,567	15,632
Business credit carryforwards	18,066	0
Loss carryforwards - federal	10,310	0
Lease liabilities	4,523	6,354
Property and equipment	2,613	59,207
Other	4,206	4,092
Valuation allowances	(125,462)	(129,408)
Total deferred tax assets	19,658	24,946
Deferred tax liabilities
CO2 and other contracts	(17,208)	(20,030)
Operating lease right-of-use assets	(4,088)	(6,190)
Total deferred tax liabilities	(21,296)	(26,220)
Total net deferred tax liability	$ (1,638)	$ (1,274)