Leases - Additional information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Leases [Abstract]
Operating leases right of use assets	$ 4,261,000	$ 4,329,000
Short-term lease liabilities	1,520,000
Long-term lease liabilities	2,855,000		$ 102,000
Short-term lease cost	$ 1,870,000
Weighted-average remaining lease term	3 years 10 months 24 days
Weighted-average discount rate	3.78%
Additional interest factor	1.375%
Lease liabilities paid	$ 247,000
ROU assets in exchange for new operating lease liabilities	1,761,000
Lease income	$ 856,000