Leases - Summary of Information Related to ROU Assets and Related Lease Liabilities (Detail) - USD ($) $ in Thousands		3 Months Ended	6 Months Ended
	Jan. 01, 2019	Jun. 30, 2019	Jun. 30, 2019
Assets And Liabilities Lessee [Abstract]
Cash paid for operating lease liabilities		$ 1,914	$ 3,644
Right-of-use assets obtained in exchange for new operating lease obligations	$ 25,800	$ 1,819	$ 28,514
Weighted-average remaining lease term		4 years 2 months 12 days	4 years 2 months 12 days
Weighted-average discount rate		4.40%	4.40%