Leases - Summary of future minimum lease payments (prior period) (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Future Minimum Lease Payments [Line Items]
2019	$ 3,682
2020	2,957
2021	2,957
2022	2,957
2023	3,037
2024 and thereafter	14,622
Total future minimum lease payments (undiscounted)	$ 30,212
Prior Period [Member]
Future Minimum Lease Payments [Line Items]
2019		$ 3,764
2020		3,516
2021		3,146
2022		2,957
2023		2,957
2024 and thereafter		17,641
Total future minimum lease payments (undiscounted)		$ 33,981