Income Taxes - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Tax Credit Carryforward [Line Items]
Income tax expense (benefit)	$ 5,433	$ (8,152)	$ 22,439	$ (9,336)
Deferred income tax valuation allowance	47,787		47,787		$ 0
Income tax benefit from remeasurement of deferred income tax assets and liabilities			22,900
Income tax benefit from Internal Revenue Code			2,500	3,300
Income tax benefit from depletion expense				3,200
Income tax benefit from loss recognized before income taxes				$ 2,900
State and Local Jurisdiction
Tax Credit Carryforward [Line Items]
Deferred income tax valuation allowance	$ 47,800		$ 47,800