Leases - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Leases [Abstract]
Cumulative effect of new accounting principle in period of adoption			$ 5,500
Operating lease liabilities	$ 1,276	$ 1,276	1,600
Operating lease liabilities, long-term	3,005	3,005	$ 3,900
Lease expense recognize on a straight-line basis	600	1,100
2019	921	921		$ 2,000
2020	1,455	1,455		1,500
2021	645	645		800
2022	305	305		500
2023	181	181		400
After 2023	$ 2,767	$ 2,767		$ 4,200