Income Taxes (Effective Income Tax Rate Reconciliation) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
Federal statutory provision									$ 99,045	$ 86,229	$ 213,789
State and local income taxes									7,327	9,208	17,769
Other impact of foreign operations									(31,573)	(13,806)	(6,492)
Tax incentives/credits/exempt income									(16,292)	(10,735)	(12,130)
Outside basis differences									0	0	(27,110)
Goodwill impairments									0	58,022	0
Remeasurement of U.S. deferred tax liability									(129,612)	0	0
U.S. tax on unremitted earnings									90,916	0	0
Other, net									1,838	2,901	3,952
Total provision for income taxes	$ (32,326)	$ 17,607	$ 4,952	$ 31,416	$ 38,204	$ 23,197	$ 33,394	$ 37,024	$ 21,649	$ 131,819	$ 189,778