Income Taxes - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Taxes [Line Items]
Income tax expense (benefit) related to Tax Reform Act			$ (3,700)
Income tax expense		$ 8,453	$ 11,974	$ 17,821
Effective tax rate for income from continuing operations (as a percent)		19.50%	19.50%	32.40%
Change in valuation allowance		$ 600
Income tax expense (benefit) for change in tax rate			$ 1,700
Income tax expense (benefit) from domestic production activities deduction			1,100
Income tax expense (benefit) from stock-based compensation			2,700
Income tax expense (benefit) from release of reserves	$ 1,500
Effective income tax rate reconciliation, tax expense (benefit) foreign income tax rate differential				$ 1,300
Effective income tax rate reconciliation, tax benefit attributable to the Domestic Production Activities Deduction				1,500
Effective income tax rate reconciliation, tax credit related to research and development credits				1,100
Increase in valuation allowance against certain deferred tax assets				(1,200)
Undistributed accumulated earnings of foreign subsidiary		1,800
Reasonably expected net unrecognized benefits may be recognized		300
Total amount of net unrecognized tax benefits that would affect the effective tax rate if recognized		3,600
Amount of unrecognized tax benefit, if recognized, would be offset		1,400
Netherlands and China
Income Taxes [Line Items]
Increase in valuation allowance against certain deferred tax assets				500
China
Income Taxes [Line Items]
Change in valuation allowance			300
State
Income Taxes [Line Items]
Effective income tax rate reconciliation, state and local income taxes				$ 700
Operating loss carryforward		4,100
Deferred tax asset not recorded		4,000
State tax credit carry forwards that expire between 2019 and 2033		1,800
Foreign | China
Income Taxes [Line Items]
Operating loss carryforward		6,800
Foreign | Germany
Income Taxes [Line Items]
Operating loss carryforward		10,500
Foreign | Netherlands
Income Taxes [Line Items]
Operating loss carryforward		5,100
Foreign Tax Error | Restatement Adjustment
Income Taxes [Line Items]
Income tax expense		700	$ 700
Maximum
Income Taxes [Line Items]
Estimated income tax expense (benefit) from repatriation tax		$ 500