Income Taxes - Components of Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current:
Federal		$ (1,694)	$ 18,951	$ 409
State		120	507	40
Foreign		1,394	2,072	3,482
Current income tax (benefit) expense		(180)	21,530	3,931
Deferred:
Federal		(486)	1,038	(2,357)
State		(153)	(580)	(229)
Foreign		447	(1,645)	174
Deferred income tax benefit		(192)	(1,187)	(2,412)
Income tax (benefit) expense	$ 1,000	$ (372)	$ 20,343	$ 1,519