Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Tax Disclosure [Abstract]
Income tax expense	$ 39,390	$ 50,997	$ 97,933	$ 112,251
Effective tax rate	32.00%	37.00%	32.00%	34.00%
Federal statutory rate			35.00%	35.00%
State income tax expense	$ 2,120	$ 2,726	$ 5,335	$ 6,560
Undistributed Earnings of Foreign Subsidiaries	5,456	939	8,921	6,201
Effective Income Tax Rate Reconciliation, Deduction, Qualified Production Activity, Amount	4,413	5,015	9,735	10,183
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount	2,701	$ 3,957	4,701	$ 6,788
Deferred Tax Assets, Tax Credit Carryforwards, Foreign	41,000		41,000
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation			781
Second component of tax deductible goodwill, net of tax	$ 800		$ 800