Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Income tax expense	$ 40,124	$ 21,157	$ 173,399	$ 119,090
Effective tax rate	31.00%	24.00%	34.00%	31.00%
Federal statutory rate			35.00%	35.00%
Effective Income Tax Rate Reconciliation, Deduction, Qualified Production Activity, Amount	$ 2,800	$ 2,784	$ 13,100	$ 12,519
Undistributed Earnings of Foreign Subsidiaries	(5,500)	3,443	1,200	12,364
State income tax expense	2,400	800	8,400	6,100
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount	8,400	(2,300)	900	(7,000)
Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount	600	$ 6,700	(2,000)	$ 4,000
Deferred Tax Assets, Tax Credit Carryforwards, Foreign	28,000		28,000
Second component of tax deductible goodwill, net of tax	$ 1,200		$ 1,200