Nature of Operations and Basis of Presentation (Income Taxes) (Details) - USD ($)		3 Months Ended		9 Months Ended
	Mar. 27, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Income tax benefit, CARES Act	$ 17,800,000
Federal income tax expense (benefit)		$ (17,987,000)	$ (2,186,000)	$ (52,176,000)	$ 7,595,000
Liability for unrecognized tax benefits		$ 0		$ 0		$ 0