Income Taxes (Statutory Tax Rate Impact on Income Tax Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Computed expected tax benefit (expense)	$ 231,579	$ (206,862)	$ (460,885)
State and local income taxes, net of federal income taxes	74,426	(17,001)	(38,991)
Dividends received deductions	0	0	1,969
Executive compensation	(7,114)	0	0
Change in valuation allowance affecting tax expense	(189)	(384)	0
Change in state tax rate due to acquisition	(117,496)	0	0
Change in state tax rate due to law change	37,108	0	0
Change in tax rate due to Tax Act	0	347,979	0
Deductible stock compensation	(131)	14,116	1,700
Goodwill impairment	(30,960)	0	0
Other, net	(2,348)	(4,326)	(38)
Income tax benefit (expense)	$ 184,875	$ 133,522	$ (496,245)