Regulatory Matters - Schedule of Regulatory Capital Ratios Under the Basel III Regulatory Capital Framework (Detail) $ in Thousands	Dec. 31, 2021 USD ($)		Dec. 31, 2020 USD ($)
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital to Risk-Weighted Assets, Actual Ratio	20.34		22.03
Tier1 Capital to Risk-Weighted Assets, Actual Ratio	19.35		20.79
Common Equity Tier1 Capital to Risk-Weighted Assets, Actual Ratio	19.35		20.79
Leverage Ratio, Actual Ratio	11.13		11.86
Consolidated [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital to Risk-Weighted Assets, Actual Amount	$ 1,425,907		$ 1,273,749
Tier1 Capital to Risk-Weighted Assets, Actual Amount	1,356,006		1,201,729
Common Equity Tier1 Capital to Risk-Weighted Assets, Actual Amount	1,356,006		1,201,729
Leverage Ratio, Actual Amount	$ 1,356,006		$ 1,201,729
Total Capital to Risk-Weighted Assets, Actual Ratio	20.34		22.03
Tier1 Capital to Risk-Weighted Assets, Actual Ratio	19.35		20.79
Common Equity Tier1 Capital to Risk-Weighted Assets, Actual Ratio	19.35		20.79
Leverage Ratio, Actual Ratio	11.13		11.86
Consolidated [Member] | Minimum [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital to Risk-Weighted Assets, Required To Be Considered Well Capitalized, Amount	$ 700,955		$ 578,131
Tier1 Capital to Risk-Weighted Assets, Required To Be Considered Well Capitalized, Amount	$ 420,573		$ 346,879
Total Capital to Risk-Weighted Assets, Required To Be Considered Well Capitalized , Ratio	10.00		10.00
Tier1 Capital to Risk-Weighted Assets, Required To Be Considered Well Capitalized , Ratio	6.00		6.00
Consolidated [Member] | Minimum [Member] | Basel III Fully Phased-In [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital to Risk-Weighted Assets, Minimum Capital Required	$ 736,003	[1]	$ 607,038
Tier1 Capital to Risk-Weighted Assets, Minimum Capital Required	595,812	[1]	491,412
Common Equity Tier1 Capital to Risk-Weighted Assets, Minimum Capital Required	490,669	[1]	404,692
Leverage Ratio, Minimum Capital Required	$ 487,459	[1]	$ 405,268
Total Capital to Risk-Weighted Assets, Minimum Capital Required	10.50	[1]	10.50
Tier1 Capital to Risk-Weighted Assets, Minimum Capital Required	8.50	[1]	8.50
Common Equity Tier1 Capital to Risk-Weighted Assets, Minimum Capital Required, Ratio	7.00	[1]	7.00
Leverage Ratio, Minimum Capital Required, Ratio	4.00	[1]	4.00
Parent Company [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital to Risk-Weighted Assets, Actual Amount	$ 1,258,965		$ 1,123,275
Tier1 Capital to Risk-Weighted Assets, Actual Amount	1,189,064		1,051,255
Common Equity Tier1 Capital to Risk-Weighted Assets, Actual Amount	1,189,064		1,051,255
Leverage Ratio, Actual Amount	$ 1,189,064		$ 1,051,255
Total Capital to Risk-Weighted Assets, Actual Ratio	17.99		19.47
Tier1 Capital to Risk-Weighted Assets, Actual Ratio	17.00		18.22
Common Equity Tier1 Capital to Risk-Weighted Assets, Actual Ratio	17.00		18.22
Leverage Ratio, Actual Ratio	9.79		10.41
Parent Company [Member] | Minimum [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital to Risk-Weighted Assets, Required To Be Considered Well Capitalized, Amount	$ 699,623		$ 576,981
Tier1 Capital to Risk-Weighted Assets, Required To Be Considered Well Capitalized, Amount	559,698		461,585
Common Equity Tier1 Capital to Risk-Weighted Assets, Required To Be Considered Well Capitalized, Amount	454,755		375,038
Leverage Ratio, Required To Be Considered Well Capitalized, Amount	$ 607,407		$ 505,002
Total Capital to Risk-Weighted Assets, Required To Be Considered Well Capitalized , Ratio	10.00		10.00
Tier1 Capital to Risk-Weighted Assets, Required To Be Considered Well Capitalized , Ratio	8.00		8.00
Common Equity Tier1 Capital to Risk-Weighted Assets, Required To Be Considered Well Capitalized , Ratio	6.50		6.50
Leverage Ratio, Required To Be Considered Well Capitalized , Ratio	5.00		5.00
Parent Company [Member] | Minimum [Member] | Basel III Fully Phased-In [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital to Risk-Weighted Assets, Minimum Capital Required	$ 734,604	[1]	$ 605,830
Tier1 Capital to Risk-Weighted Assets, Minimum Capital Required	594,679	[1]	490,434
Common Equity Tier1 Capital to Risk-Weighted Assets, Minimum Capital Required	489,736	[1]	403,887
Leverage Ratio, Minimum Capital Required	$ 485,926	[1]	$ 404,002
Total Capital to Risk-Weighted Assets, Minimum Capital Required	10.50	[1]	10.50
Tier1 Capital to Risk-Weighted Assets, Minimum Capital Required	8.50	[1]	8.50
Common Equity Tier1 Capital to Risk-Weighted Assets, Minimum Capital Required, Ratio	7.00	[1]	7.00
Leverage Ratio, Minimum Capital Required, Ratio	4.00	[1]	4.00

[1] *At December 31, 2021 the Capital Conservative Buffer Basel III has been fully phased-in.