Foreign Currency Translation - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Foreign Currency [Abstract]
Gain (loss) on foreign currency translation	$ 1,091	$ (733)	$ (2,755)	$ (617)
Foreign currency translation gain (loss)	$ 6,353	$ 3,000	$ 20,900	$ 7,955