Income Taxes - Provision For Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current tax expense (benefit):
U.S. Federal	$ (236)	$ (37,854)	$ (32,272)
State	561	20	(34)
Foreign	10,301	10,440	11,411
Total current	10,626	(27,394)	(20,895)
Deferred tax expense (benefit):
U.S. Federal	(3,848)	2,670	(2,624)
State	(796)	(181)	179
Foreign	(1,089)	863	1,942
Total deferred	(5,733)	3,352	(503)
Total income tax expense (benefit)	$ 4,893	$ (24,042)	$ (21,398)