Leases - Schedule of Maturities of the Lease Liabilities (Detail) $ in Thousands	Mar. 31, 2019 USD ($)
Leases [Abstract]
2019 (excluding the three months ended March 31, 2019)	$ 1,772
2020	2,380
2021	2,278
2022	2,216
2023	2,136
Thereafter	6,048
Total lease payments	16,830
Less imputed interest	3,260
Total operating lease liabilities	$ 13,570