Income Taxes - Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Loss Carryforwards [Line Items]
Current Federal Tax Expense (Benefit)	$ 119,883	$ 45,314	$ 82,532
Current State and Local Tax Expense (Benefit)	(6,156)	7,022	18,022
Current International Tax Expense (Benefit)	134,987	110,208	85,310
Current Income Tax Expense (Benefit)	248,714	162,544	185,864
Deferred Federal Income Tax Expense (Benefit)	31,168	29,973	12,127
Deferred State and Local Income Tax Expense (Benefit)	13,534	7,161	(1,828)
Deferred International Income Tax Expense (Benefit)	(6,290)	(9,004)	(4,466)
Deferred income taxes	38,412	28,130	5,833
Provision for income taxes	$ 287,126	$ 190,674	$ 191,697