Income Taxes - Reconciliation of Effective Tax Rate, Amount (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Income taxes at the statutory rate	$ 2,455	$ (5,964)	$ (8,985)	$ (9,181)
State taxes, net of federal benefit	25	(1,114)	117	(521)
Foreign tax rate differential	(3,403)	2,436	2,263	6,018
Permanent differences	1,464	2,934	3,190	265
Uncertain tax positions	1,821	(292)	666	(928)
Valuation allowance	13	(176)	330	87,404
Return to provision adjustments	(512)	(33)	(509)	(33)
Other	302	11	21	0
Income tax benefit (expense)	$ 2,165	$ (2,198)	$ (2,907)	$ 83,024