Income Taxes - Summary of Reconciliation Between the Statutory Tax Rate and Actual Effective Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Statutory federal tax rate	21.00%	21.00%	21.00%
State taxes, net of federal benefit	1.10%	1.60%	1.10%
Tax-exempt interest	(1.70%)	(2.80%)	(2.20%)
Cash surrender value on BOLI	(0.50%)	(0.80%)	(0.50%)
Tax credits	(3.20%)	(6.30%)	(4.20%)
Affordable housing cost amortization, net of tax benefits	2.20%	2.50%	1.40%
Other items	0.70%	1.50%	1.10%
Effective tax rate	19.60%	16.70%	17.70%