Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 5,002	$ 9,391	$ 14,671	$ 22,773
Foreign currency translation gain (loss)	4,325	(2,236)	12,460	(4,641)
Unrealized gain on investments	0	34	0	252
Other comprehensive income (loss)	4,325	(2,202)	12,460	(4,389)
Comprehensive income	$ 9,327	$ 7,189	$ 27,131	$ 18,384