Leases - Summary of Company's Leases (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	[1]
Leases [Abstract]
Lease liabilities	$ 7,113	$ 5,506
Right-of-use asset	$ 5,645	$ 5,328
Weighted average remaining lease term (years)	5 years 10 months 20 days
Weighted average discount rate	2.18%

[1] Derived from audited December 31, 2020 Consolidated Financial Statements.