Income Taxes - Components of Income Tax Expense (Benefit) from Continuing Operations (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Current U.S. federal									$ 21,069	$ 94,873	$ 273,205
Current State and local									12,282	18,810	35,057
Current Sub-total									33,351	113,683	308,262
Deferred U.S. federal									61,144	(381,063)	32,783
Deferred State and local									18,635	(33,993)	6,157
Deferred Sub-total									79,779	(415,056)	38,940
Income tax (benefit) expense from continuing operations	$ 46,034	$ (22,422)	$ 32,816	$ 56,702	$ (219,767)	$ (20,087)	$ (9,905)	$ (51,614)	$ 113,130	$ (301,373)	$ 347,202