Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Taxes [Line Items]
Tax cuts and jobs act of 2017, incomplete accounting, change in tax rate, deferred tax asset, provisional income tax expense		$ 19,400
Tax cuts and jobs act of 2017, incomplete accounting, transition tax for accumulated foreign earnings, provisional income tax expense		17,400	$ 17,400
Income tax expense (benefit)	$ 1,000		(372)	$ 20,343	$ 1,519
Decrease in deferred income taxes	1,800		689	(1,740)	(2,002)
Tax Cuts And Jobs Act of 2017, Incomplete Accounting, Change in Tax Rate, Provisional Income Tax Expense (Benefit)		(2,000)	(2,000)
Deferred income tax assets, domestic	7,200	7,700	7,200	7,700
Deferred income tax assets, foreign	6,500	7,900	6,500	7,900
Deferred Tax Assets, Valuation Allowance	$ 1,924	$ 1,631	1,924	1,631
Net increase (decrease) in total valuation allowance			$ (300)	$ (700)	$ 100
Minimum
Income Taxes [Line Items]
Deferred income tax assets, operating loss carryforwards expiration period			1 year
Tax returns examination statute of limitations period			3 years
Maximum
Income Taxes [Line Items]
Deferred income tax assets, operating loss carryforwards expiration period			9 years
Tax returns examination statute of limitations period			4 years