Employee Benefit Plans - Additional Information (Detail) $ in Thousands	12 Months Ended
Dec. 31, 2021 USD ($) Employee shares	Dec. 31, 2020 USD ($) Employee shares	Dec. 31, 2019 USD ($) Employee shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum percentage of eligible compensation on a pre-tax or post-tax basis for eligible employees to save	1.00%
Employee contribution matching percentage	50.00%
Percentage of total eligible compensation, contribution by Bank, maximum limit	6.00%
Vesting percentage in participant's deferral contributions and employer matching contributions	100.00%
Vesting period	6 years
Defined contribution plan employer matching contribution description	In order to be eligible for discretionary contributions, employees must work 1,000 hours in the plan year and be employed on the last day of the year.
Employer matching contribution and the discretionary contribution \| $	$ 1,500	$ 1,000	$ 1,200
Restricted stock awards, shares issued	48,750	37,382	38,100
Awards grants originated in 2016, 2017 and 2018 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of employees, received the stock \| Employee			3
Four employees received shares from awards granted due to retirement			14,300
Awards grants originated in 2019, 2018 and 2017 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of employees, received the stock \| Employee		1
Number of shares vested		1,050
Awards grants originated in 2017, 2018 and 2019 and 2020 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of employees, received the stock \| Employee		8
Number of shares vested		10,890
Awards grants originated in 2018, 2019 and 2020 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of employees, received the stock \| Employee	7
Number of shares vested	4,425
Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Restricted stock awards, shares issued	48,750	37,382	38,100
Stock issued to number of employees \| Employee	96	92	94
Shares vest under the plan	100.00%	100.00%	100.00%
Shares forfeited due to employee termination	2,575	2,175	3,220
Number of shares vested	23,270	35,431	40,370
Number of employees, received the stock \| Employee	50	58	63
Number of shares vested	4,425	10,890	14,300
Compensation expense \| $	$ 822	$ 1,000	$ 1,100
Unrecognized compensation cost related to the nonvested portion of restricted stock awards under the plan \| $	$ 1,500
Unrecognized compensation cost related to the nonvested portion of restricted stock awards under the plan, period for recognition	3 years
Restricted Stock Awards [Member] \| 2018 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares vested	18,845
Number of employees, received the stock \| Employee	50
Restricted Stock Awards [Member] \| 2019 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares vested		1,600
Number of employees, received the stock \| Employee		3
Restricted Stock Awards [Member] \| 2016 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares vested			26,070
Number of employees, received the stock \| Employee			63
Restricted Stock Awards [Member] \| 2017 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares vested		21,340
Number of employees, received the stock \| Employee		53
Restricted Stock Awards [Member] \| Immediate Vesting [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of employees, received the stock \| Employee		1
Number of shares vested		551,000

Defined contribution plan employer matching contribution description.

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Minimum percentage of eligible compensation on pre tax or post tax basis for eligible employees to save.

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Number of awards granted to four employees on retirement.

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Number of awards granted to one employee on retirement.

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Share based compensation arrangement by share based payment award equity instruments other than options share vested percentage.

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Share based compensation arrangement by share based payment award number of employee share issued.

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Share based compensation arrangement by share based payment award number of employees.

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Amount of discretionary contributions made by an employer to a defined contribution plan.

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Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

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Percentage of employer's matching contributions to a defined contribution plan that vests in a given year.

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Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Total number of shares issued during the period, including shares forfeited, as a result of Restricted Stock Awards.

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