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Summary of Significant Accounting Policies - Additional Information (Detail) |  | 3 Months Ended | 12 Months Ended |
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Apr. 10, 2023 | Dec. 31, 2023 USD ($) | Sep. 30, 2023 USD ($) | Jun. 30, 2023 USD ($) | Mar. 31, 2023 USD ($) | Dec. 31, 2022 USD ($) | Sep. 30, 2022 USD ($) | Jun. 30, 2022 USD ($) | Mar. 31, 2022 USD ($) | Dec. 31, 2023 USD ($) Bank | Dec. 31, 2022 USD ($) | Dec. 31, 2021 USD ($) | Jan. 01, 2023 USD ($)
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Period for federal funds sold outstanding |  |  |  |  |  |  |  |  |  | 1 day |  |  |
Accrued interest receivable |  |  |  |  |  |  |  |  |  | $ 10,200,000 | $ 8,600,000 |  |
Delinquent loan is well secured and process of collection |  |  |  |  |  |  |  |  |  | 90 days |  |  |
Mortgage loans charged off days past due |  |  |  |  |  |  |  |  |  | 180 days |  |  |
Consumer and credit card loans to accrue interest charged off |  |  |  |  |  |  |  |  |  | 120 days |  |  |
Unrecognized interest income until loan balance reduced |  |  |  |  |  |  |  |  |  | $ 0 |  |  |
Maximum time for re-evaluation (in months) |  |  |  |  |  |  |  |  |  | 12 months |  |  |
Re-evaluation period for real estate |  |  |  |  |  |  |  |  |  | 2 years |  |  |
Amount of fair value of capital over carrying value |  |  | $ 8,800,000 |  |  |  |  |  |  |  |  |  |
Percentage of fair value of capital over carrying value |  |  | 2.70% |  |  |  |  |  |  |  |  |  |
Number of times fair value of capital in excess of carrying value of goodwill description |  |  |  |  |  |  |  |  |  | over 0.1 times |  |  |
Foreclosed real estate |  |  |  |  |  |  |  |  |  | $ 0 | 0 |  |
Percentage of likelihood of realization of recognized tax benefit, minimum |  |  |  |  |  |  |  |  |  | 50.00% |  |  |
Provision for credit losses - loans |  | $ 278,000 | $ 460,000 | $ 143,000 | $ 817,000 | $ 755,000 | $ 1,637,000 | $ 1,628,000 | $ 580,000 | $ 1,698,000 | 4,600,000 | $ 3,444,000 |
Number of peer group banks | Bank |  |  |  |  |  |  |  |  |  | 307 |  |  |
Reserve portion of allowance of credit loss |  |  |  |  |  |  |  |  |  | $ 400,000 | $ 2,000,000 |  |
Captives provision existence period | 10 years |  |  |  |  |  |  |  |  |  |  |  |
Commercial and Agricultural [member] |  |  |  |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of external and independent loan |  |  |  |  |  |  |  |  |  | 35.00% |  |  |
ASU 2016-13 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Change in accounting principle, accounting standards update, adopted [true false] |  | true |  |  |  |  |  |  |  | true |  |  |
Change in accounting principle, accounting standards update, adoption date |  | Jan. 01, 2023 |  |  |  |  |  |  |  | Jan. 01, 2023 |  |  |
Change in accounting principle, accounting standards update, immaterial effect [true false] |  | true |  |  |  |  |  |  |  | true |  |  |
Current expected credit losses |  | $ 3,600,000 |  |  |  |  |  |  |  | $ 3,600,000 |  |  | $ 26,043,000
Tax impact portion of deferred tax asset |  | 1,100,000 |  |  |  |  |  |  |  | 1,100,000 |  |  |
ASU 2016-13 [Member] | Letter of credit |  |  |  |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Current expected credit losses |  | 3,400,000 |  |  |  |  |  |  |  | 3,400,000 |  |  |
ASU 2016-13 [Member] | Unfunded loan commitment |  |  |  |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Current expected credit losses |  | $ 900,000 |  |  |  |  |  |  |  | $ 900,000 |  |  |
ASU 2022-02 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Change in accounting principle, accounting standards update, adopted [true false] |  | true |  |  |  |  |  |  |  | true |  |  |
Change in accounting principle, accounting standards update, adoption date |  | Jan. 01, 2023 |  |  |  |  |  |  |  | Jan. 01, 2023 |  |  |
Maximum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Maturity period of cash equivalents |  |  |  |  |  |  |  |  |  | 3 months |  |  |
Asset value of peer group banks |  |  |  |  |  |  |  |  |  | $ 5,000,000,000 |  |  |
Percentage of captive claims listed transaction loss ratio | 65.00% |  |  |  |  |  |  |  |  |  |  |  |
Percentage of captive claims transaction of interest loss ratio | 70.00% |  |  |  |  |  |  |  |  |  |  |  |
Minimum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Market Capitalization From Increased Bank Equities |  | $ 85,000,000 |  |  |  |  |  |  |  |  |  |  |
Increase in fair value estimate |  |  |  |  |  |  |  |  |  | $ 8,800,000 |  |  |

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