Leases - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Jan. 01, 2019
Leases [Abstract]
Operating lease right-of-use asset	$ 44,222	$ 10,400
Operating lease liability	45,379	$ 10,400
Operating lease cost	2,300
Operating lease liability current	$ 19,787
Weighted average remaining lease term	3 years 6 months
Weighted average discount cate	5.60%