Income Taxes (Schedule of Components of Income Tax Expense (Benefit)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Current Expense, Domestic	$ 162,305	$ 124,231	$ 188,712
Deferred Expense (Benefit), Domestic	17	27,616	(63,134)
Domestic, Total	162,322	151,847	125,578
Current Expense, Foreign	23,375	9,030	13,963
Deferred Expense (Benefit), Foreign	(13,880)	8,058	23,487
Foreign, Total	9,495	17,088	37,450
Current Expense, Total	185,680	133,261	202,675
Deferred Expense (Benefit), Total	(13,863)	35,674	(39,647)
Total expense	171,817	168,935	163,028
Income (Loss) from Continuing Operations before Income Taxes, Domestic	831,000	739,000	755,000
Income (Loss) from Continuing Operations before Income Taxes, Foreign	$ (126,000)	$ 114,000	$ 57,000