Income Taxes - Components of Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current:
Federal	$ 409	$ 199	$ 3,780
State	40	78	367
Foreign	3,482	562	4,433
Current income tax expense	3,931	839	8,580
Deferred:
Federal	(2,357)	88	306
State	(229)	9	30
Foreign	174	(943)	(5,043)
Deferred income tax benefit	(2,412)	(846)	(4,707)
Income tax expense (benefit)	$ 1,519	$ (7)	$ 3,873