Income Tax (Provision for Income Tax Expense Computed from Statutory Rate to Pre-tax Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount	$ 365,381	$ 260,678	$ 352,987
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount	(13,974)	(9,950)	(12,483)
Income Tax Reconciliation Foreign Income Tax Basis Differential	(17,770)	(32,472)	(8,256)
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount	10,963	19,157	2,076
Effective Income Tax Rate Reconciliation, Tax Contingency, Domestic, Amount	111	88	(9,083)
Income Tax Reconciliation Change In Foreign Enacted Tax Rate	0	0	280
Income Tax Reconciliation Subpart F	1,783	3,473	6,132
Effective Income Tax Rate Reconciliation, Tax Credit, Foreign, Amount	(1,683)	(1,936)	(1,045)
Effective Income Tax Rate Reconciliation, Prior Year Income Taxes, Amount	(1,473)	1,482	(8,123)
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount	(835)	2,109	2,001
Income Tax Expense (Benefit)	$ 342,503	$ 242,629	$ 324,486
Effective Income Tax Rate Reconciliation, Percent	32.80%	32.60%	32.20%