Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Tax Disclosure [Abstract]
Income tax expense	$ 60,193	$ 39,390	$ 133,275	$ 97,933
Effective tax rate	36.00%		35.00%	32.00%
Federal statutory rate			35.00%	35.00%
Effective Income Tax Rate Reconciliation, Deduction, Qualified Production Activity, Amount	$ 4,442	4,413	$ 10,304	$ 9,735
Undistributed Earnings of Foreign Subsidiaries	(2,559)	(5,456)	(6,695)	(8,921)
State income tax expense	2,626	2,120	6,042	5,335
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount	5,244	$ 2,701	7,510	$ 4,701
Deferred Tax Assets, Tax Credit Carryforwards, Foreign	34,000		34,000
Second component of tax deductible goodwill, net of tax	$ 800		$ 800