Fair Value Measurement and Fair Value of Financial Instruments- Carrying Values and Fair Values of Company's Financial Instruments (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Financial Assets:
Carrying Value	$ 934,947	$ 824,956
Fair Value	753,565	815,211
Federal Home Loan Bank and other membership bank stocks, Carrying Value	21,046	9,049
Federal Home Loan Bank and other membership bank stocks, Fair Value	21,046	9,049
Loans	7,499,947	5,918,101
Fair Value	7,349,734	5,900,876
Financial Liabilities:
Certificates of deposit, Carrying Value	1,034,181	759,227
Certificates of deposit, Fair Value	998,659	753,483
Other borrowings, Carrying Value	25,000	25,000
Other borrowings, Fair Value	22,902	24,604
Subordinated debt, Carrying Value	194,148	179,043
Subordinated debentures, Fair Value	157,228	175,243
U.S. government agencies
Financial Assets:
Carrying Value	16,296	18,672
Fair Value	15,576	18,965
Mortgage-backed securities, residential
Financial Assets:
Carrying Value	357,453	370,247
Fair Value	295,488	364,976
Collateralized mortgage obligations, residential
Financial Assets:
Carrying Value	13,328	13,921
Fair Value	10,948	14,089
Mortgage-backed securities, multifamily
Financial Assets:
Carrying Value	5,117	2,710
Fair Value	4,349	2,734
Obligations of states and political subdivisions
Financial Assets:
Carrying Value	539,888	416,566
Fair Value	424,722	411,576
Corporate bonds
Financial Assets:
Carrying Value	2,865	2,840
Fair Value	2,482	2,871
Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial Assets:
Fair Value	0	0
Federal Home Loan Bank and other membership bank stocks, Fair Value	0	0
Fair Value	0	0
Financial Liabilities:
Certificates of deposit, Fair Value	0	0
Other borrowings, Fair Value	0	0
Subordinated debentures, Fair Value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| U.S. government agencies
Financial Assets:
Fair Value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Mortgage-backed securities, residential
Financial Assets:
Fair Value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Collateralized mortgage obligations, residential
Financial Assets:
Fair Value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Mortgage-backed securities, multifamily
Financial Assets:
Fair Value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Obligations of states and political subdivisions
Financial Assets:
Fair Value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Corporate bonds
Financial Assets:
Fair Value	0	0
Significant Other Observable Inputs (Level 2)
Financial Assets:
Fair Value	729,221	814,379
Federal Home Loan Bank and other membership bank stocks, Fair Value	21,046	9,049
Fair Value	0	0
Financial Liabilities:
Certificates of deposit, Fair Value	998,659	753,483
Other borrowings, Fair Value	22,902	24,604
Subordinated debentures, Fair Value	0	0
Significant Other Observable Inputs (Level 2) \| U.S. government agencies
Financial Assets:
Fair Value	15,576	18,965
Significant Other Observable Inputs (Level 2) \| Mortgage-backed securities, residential
Financial Assets:
Fair Value	295,488	364,976
Significant Other Observable Inputs (Level 2) \| Collateralized mortgage obligations, residential
Financial Assets:
Fair Value	10,948	14,089
Significant Other Observable Inputs (Level 2) \| Mortgage-backed securities, multifamily
Financial Assets:
Fair Value	4,349	2,734
Significant Other Observable Inputs (Level 2) \| Obligations of states and political subdivisions
Financial Assets:
Fair Value	400,378	410,744
Significant Other Observable Inputs (Level 2) \| Corporate bonds
Financial Assets:
Fair Value	2,482	2,871
Significant Unobservable Inputs (Level 3)
Financial Assets:
Fair Value	24,344	832
Federal Home Loan Bank and other membership bank stocks, Fair Value	0	0
Fair Value	7,349,734	5,900,876
Financial Liabilities:
Certificates of deposit, Fair Value	0	0
Other borrowings, Fair Value	0	0
Subordinated debentures, Fair Value	157,228	175,243
Significant Unobservable Inputs (Level 3) \| U.S. government agencies
Financial Assets:
Fair Value	0	0
Significant Unobservable Inputs (Level 3) \| Mortgage-backed securities, residential
Financial Assets:
Fair Value	0	0
Significant Unobservable Inputs (Level 3) \| Collateralized mortgage obligations, residential
Financial Assets:
Fair Value	0	0
Significant Unobservable Inputs (Level 3) \| Mortgage-backed securities, multifamily
Financial Assets:
Fair Value	0	0
Significant Unobservable Inputs (Level 3) \| Obligations of states and political subdivisions
Financial Assets:
Fair Value	24,344	832
Significant Unobservable Inputs (Level 3) \| Corporate bonds
Financial Assets:
Fair Value	$ 0	$ 0

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Other Borrowings Fair Value Disclosure

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Amount excluding accrued interest, after allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity).

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Fair value of subordinated debt obligations including, but not limited to, subordinated loan, subordinated bond, subordinated debenture or junior debt.

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Federal Home Loan Bank (FHLB) stock represents an equity interest in a FHLB. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

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Amortized cost excluding accrued interest, after allowance for credit loss, of financing receivable. Excludes net investment in lease.

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Fair value of investment in debt security measured at amortized cost (held-to-maturity).

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Fair value portion of investments in Federal Home Loan Bank (FHLBank) stock.

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Fair value portion of an agreement for an unconditional promise by the maker to pay the holder a definite sum of money at a future date.

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The carrying amount as of the balance sheet date for the aggregate of other miscellaneous borrowings owed by the reporting entity.

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