Income Taxes - Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current:
Federal	$ 14,299	$ (90)
State	141	5	$ 1
Foreign	3,287	5,915	9,140
Total current	17,727	5,830	9,141
Deferred:
Federal	6,043	(2,985)	338
State	(200)	115	(135)
Foreign	7,210	(2,097)	(640)
Total deferred	13,053	(4,967)	(437)
Total	$ 30,780	$ 863	$ 8,704