Leases - Additional information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating leases right of use assets	$ 4,624,000
Short-term lease liabilities	1,551,000	$ 1,629,000
Long-term lease liabilities	3,225,000	2,968,000
Short-term lease cost	$ 1,968,000	1,943,000
Weighted-average remaining lease term	4 years 1 month 6 days
Weighted-average discount rate	2.97%
Additional interest factor	1.375%
Lease liabilities paid	$ 1,876,000	1,930,000
ROU assets in exchange for new operating lease liabilities	2,267,000	2,029,000
Lease income	792,000	792,000	$ 792,000
Operating lease liability additions	$ 2,256,000	$ 1,935,000
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Operating leases right of use assets