Income Taxes (Schedule of Components of Income Tax Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current Federal Tax Expense (Benefit)	$ 120,634	$ 146,915	$ 111,047
Current State Tax Expense (Benefit)	11,252	15,713	10,882
Current Foreign Tax Expense (Benefit)	22,946	14,508	13,837
Current Income Tax Expense (Benefit)	154,832	177,136	135,766
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred Federal Income Tax Expense (Benefit)	12,140	12,563	5,036
Deferred State Income Tax Expense (Benefit)	2,515	1,300	(1,373)
Deferred Foreign Income Tax Expense (Benefit)	(3,013)	5,753	(2,456)
Deferred Income Tax Expense (Benefit)	11,642	19,616	1,207
Tax expense (benefit) relating to uncertain tax positions, including accrued interest	(1,612)	4,338	(7,818)
Income Tax Expense (Benefit)	$ 164,862	$ 201,090	$ 129,155