Income Taxes (Schedule of Components of Income Tax Expense (Benefit)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Current Expense, Domestic	$ 188,712	$ 225,694	$ 259,539
Deferred Expense (Benefit), Domestic	(63,134)	(27,601)	3,355
Domestic, Total	125,578	198,093	262,894
Current Expense, Foreign	13,963	8,803	23,634
Deferred Expense (Benefit), Foreign	23,487	12,537	6,425
Foreign, Total	37,450	21,340	30,059
Current Expense, Total	202,675	234,497	283,173
Deferred Expense (Benefit), Total	(39,647)	(15,064)	9,780
Total expense	163,028	219,433	292,953
Income (Loss) from Continuing Operations before Income Taxes, Domestic	755,000	797,000	837,000
Income (Loss) from Continuing Operations before Income Taxes, Foreign	$ 57,000	$ (25,000)	$ 59,000