Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Loss Carryforwards [Line Items]
Deferred income Tax Expense (Benefit), Effective Income Tax Rate Reconciliation, Tax Cuts and Jobs Act of 2017 Percent	$ (2,500)
Undistributed Earnings of Foreign Subsidiaries		$ 523,300
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	$ (3,700)	$ (2,200)
Effective Income Tax Rate Reconciliation, Percent	0.80%	1.70%	8.10%
Income Tax Expense (Benefit)	$ 777	$ 1,637	$ 7,106
Foreign	8,266	3,266	4,789
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	1,029		771
Reserve for potential uncertain income tax return positions	9,144	3,265	3,115	$ 3,020
Portion of an unrecognized tax benefit netted against deferred tax asset for net operating loss carry forwards	$ 341	$ 341	341
India
Operating Loss Carryforwards [Line Items]
Foreign income tax holiday, term	5 years
Income Tax Holiday, Aggregate Dollar Amount			$ 2,900	$ 13,700
India | Minimum Alternative Tax (“MAT”)
Operating Loss Carryforwards [Line Items]
Foreign income tax holiday, term	10 years
Maximum [Member] | United States
Operating Loss Carryforwards [Line Items]
Income Tax Rate, Tax Cuts and Jobs Act of 2017 Percent	21.00%
Maximum [Member] | India
Operating Loss Carryforwards [Line Items]
Foreign tax holiday (percentage)	100.00%
Minimum [Member] | India
Operating Loss Carryforwards [Line Items]
Foreign tax holiday (percentage)	50.00%