Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Income Tax Disclosure [Abstract]
Income tax expense	$ 50,997	$ 36,559	$ 112,251	$ 75,664
Effective tax rate	37.00%	38.00%	34.00%	36.00%
Federal statutory rate			35.00%	35.00%
State income tax expense	$ 2,726	$ 1,914	$ 6,560	$ 3,803
Undistributed Earnings of Foreign Subsidiaries	939	3,303	6,201	7,190
Effective Income Tax Rate Reconciliation, Deduction, Qualified Production Activity, Amount	5,015	2,647	10,183	5,424
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense		3,090		6,424
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount	3,957	2,512	6,788	3,159
Deferred Tax Assets, Tax Credit Carryforwards		$ 1,134		$ 2,151
Deferred Tax Assets, Tax Credit Carryforwards, Foreign	37,000		37,000
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation			4,038
Second component of tax deductible goodwill, net of tax	$ 800		$ 800