Income Taxes (Effective Income Tax Rate Reconciliation) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
Federal statutory provision									$ 213,789	$ 150,920	$ 134,389
State and local income taxes									17,769	(1,379)	(1,733)
Other impact of foreign operations									(6,492)	(12,668)	(28,238)
Tax exempt income/reimbursement									(1,171)	(1,327)	(1,672)
Federal income tax credits/incentives									(10,959)	(17,905)	(10,282)
Unrealized stock compensation benefits									2,658	2,318	2,292
Resolution of U.S. tax examinations									0	(5,856)	(3,853)
Outside basis differences									(27,110)	0	(13,214)
Other, net									1,294	(1,288)	278
Total provision for income taxes	$ 44,204	$ 42,676	$ 52,351	$ 50,547	$ 33,134	$ 25,310	$ 46,335	$ 8,036	$ 189,778	$ 112,815	$ 77,967