Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)		$ 8,839	$ (1,310)	$ 15,548	$ (6,061)
Other comprehensive income (loss), net of tax
Currency translation adjustment	[1]	(837)	780	(979)	2,204
Comprehensive income (loss)		8,002	(530)	14,569	(3,857)
Net income (loss) attributable to non-controlling interest, net of tax		(16)	9	(12)	105
Total comprehensive income		$ 8,018	$ (539)	$ 14,581	$ (3,962)

[1] No other comprehensive income (loss) is attributable to non-controlling interests.