Income Taxes (Loss from Continuing Operations and Effective Tax Rate) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Loss from continuing operations before income tax	$ (64,800)	$ (24,070)	$ (18,299)	$ (120,363)
Income tax expense (benefit)	$ 4,174	$ 17,361	$ (124,516)	$ 31,732
Effective tax rate	(6.40%)	(72.10%)	680.50%	(26.40%)
Federal income tax expense (benefit), continuing operations			$ 129,000
Proceeds from income tax refunds					$ 760,000