Leases - Summary of Information Related to Leases (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Leases [Abstract]
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other assets	Other assets
Right of use asset	$ 22,513	$ 11,789
Weighted average discount rate	3.38%	2.94%
Weighted average remaining maturity (years)	29 years 6 months	5 years 6 months