Regulatory Matters - Summary of Capital Ratios (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Company
Total capital (to risk-weighted assets)
Total capital (to risk-weighted assets)	$ 721,741	$ 637,377
Total capital (to risk-weighted assets), For capital adequacy purposes	565,504	458,952
Tier 1 capital (to risk-weighted assets)
Tier 1 capital (to risk-weighted assets)	593,539	523,577
Tier 1 capital (to risk-weighted assets), For capital adequacy purposes	457,789	366,000
Common equity Tier 1 capital (to risk-weighted assets)
Common equity Tier 1 capital (to risk-weighted assets)	563,539	493,577
Common Equity Tier One Leverage Capital Required for Capital Adequacy	377,003	296,285
Tier 1 capital (to average assets)
Tier 1 capital (to average assets)	593,539	523,577
Tier 1 capital (to average assets), For capital adequacy purposes	$ 252,234	$ 222,982
Risk Based Ratios [Abstract]
Total capital (to risk-weighted assets), ratio	13.40%	13.71%
Tier 1 capital (to risk-weighted assets), ratio	11.02%	11.27%
Common equity Tier 1 capital (to risk-weighted assets), ratio	10.46%	10.62%
Tier 1 capital (to average assets), ratio	9.41%	9.39%
Common equity Tier 1 capital (to risk-weighted assets),For capital adequacy purposes, ratio	6.50%	6.50%
Total capital (to risk - weighted assets), To be well capitalized under prompt corrective action provisions, ratio	10.00%	10.00%
Tier 1 capital (to risk-weighted assets), To be well capitalized under prompt corrective action provisions, ratio	8.00%	8.00%
Tier 1 capital (to average assets), To be well capitalized under prompt corrective action provisions, ratio	5.00%	5.00%
Subsidiaries
Total capital (to risk-weighted assets)
Total capital (to risk-weighted assets)	$ 681,689	$ 605,560
Total capital (to risk-weighted assets), For capital adequacy purposes	564,981	457,912
Total capital (to risk - weighted assets), To be well capitalized under prompt corrective action provisions	538,077	463,708
Tier 1 capital (to risk-weighted assets)
Tier 1 capital (to risk-weighted assets)	639,908	565,549
Tier 1 capital (to risk-weighted assets), For capital adequacy purposes	457,365	365,170
Tier 1 capital (to risk-weighted assets), To be well capitalized under prompt corrective action provisions	430,462	370,967
Common equity Tier 1 capital (to risk-weighted assets)
Common equity Tier 1 capital (to risk-weighted assets)	639,908	565,549
Common Equity Tier One Leverage Capital Required for Capital Adequacy	376,654	295,614
Common equity Tier 1 capital (to risk-weighted assets), To be well capitalized under prompt corrective action provisions	349,750	301,410
Tier 1 capital (to average assets)
Tier 1 capital (to average assets)	639,908	565,549
Tier 1 capital (to average assets), For capital adequacy purposes	252,039	222,539
Tier 1 capital (to average assets), To be well capitalized under prompt corrective action provisions	$ 315,048	$ 278,173
Risk Based Ratios [Abstract]
Total capital (to risk-weighted assets), ratio	12.67%	13.06%
Tier 1 capital (to risk-weighted assets), ratio	11.89%	12.20%
Common equity Tier 1 capital (to risk-weighted assets), ratio	11.89%	12.20%
Tier 1 capital (to average assets), ratio	10.16%	10.17%
Total capital (to risk-weighted assets), For capital adequacy purposes , ratio	10.50%	9.875%
Tier 1 capital (to risk-weighted assets), For capital adequacy purposes, ratio	8.50%	7.875%
Common equity Tier 1 capital (to risk-weighted assets),For capital adequacy purposes, ratio	7.00%	6.375%
Tier 1 capital (to average assets), For capital adequacy purposes, ratio	4.00%	4.00%

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Common equity tier one risk based capital required to be well capitalized

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Common equity Tier 1 capital (to risk-weighted assets) [Abstract]

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