Income Taxes (Schedule of Components of Income Tax Expense (Benefit)) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Current Expense, Domestic		$ 259,539	$ 179,150	$ 258,337
Deferred Expense (Benefit), Domestic		3,355	31,145	28,029
Domestic, Total		262,894	210,295	286,366
Current Expense, Foreign		23,634	(2,318)	12,969
Deferred Expense (Benefit), Foreign		6,425	19,946	3,258
Foreign, Total		30,059	17,628	16,227
Current Expense, Total		283,173	176,832	271,306
Deferred Expense (Benefit), Total		9,780	51,091	31,287
Total expense	$ (302,593)	292,953	227,923	302,593
Income (Loss) from Continuing Operations before Income Taxes, Domestic		837,000	689,000	910,000
Income (Loss) from Continuing Operations before Income Taxes, Foreign		$ 59,000	$ 43,000	$ 42,000