Nature of Operations and Basis of Presentation - Income Taxes (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Income tax benefit, CARES Act			$ 0	$ 17,768,000
Federal income tax benefit	$ 4,834,000	$ 17,987,000	(1,690,000)	52,176,000
Liability for unrecognized tax benefits	$ 0		0		$ 0
Payment for income taxes			5,345,000	125,000
Federal tax refund received			$ 0	$ 0