Fair Value Measurement and Fair Value of Financial Instruments- Carrying Values and Fair Values of Company's Financial Instruments (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Financial Assets:
Carrying Value	$ 940,786	$ 824,956
Fair Value	859,928	815,211
Federal Home Loan Bank and other membership bank stocks, Carrying Value	10,415	9,049
Federal Home Loan Bank and other membership bank stocks, Fair Value	10,415	9,049
Loans	7,070,681	5,918,101
Fair Value	7,064,268	5,900,876
Financial Liabilities:
Certificates of deposit, Carrying Value	846,205	759,227
Certificates of deposit, Fair Value	828,415	753,483
Other borrowings, Carrying Value	25,000	25,000
Other borrowings, Fair Value	23,662	24,604
Subordinated debt, Carrying Value	193,904	179,043
Subordinated debentures, Fair Value	176,848	175,243
U.S. Treasury and U.S. government agencies
Financial Assets:
Carrying Value	21,795	18,672
Fair Value	21,599	18,965
Mortgage-backed securities, residential
Financial Assets:
Carrying Value	367,084	370,247
Fair Value	339,711	364,976
Collateralized mortgage obligations, residential
Financial Assets:
Carrying Value	14,433	13,921
Fair Value	13,317	14,089
Mortgage-backed securities, multifamily
Financial Assets:
Carrying Value	4,270	2,710
Fair Value	4,066	2,734
Obligations of states and political subdivisions
Financial Assets:
Carrying Value	530,354	416,566
Fair Value	478,480	411,576
Corporate bonds
Financial Assets:
Carrying Value	2,850	2,840
Fair Value	2,755	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. Treasury and 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	816,133	814,379
Federal Home Loan Bank and other membership bank stocks, Fair Value	10,415	9,049
Fair Value	0	0
Financial Liabilities:
Certificates of deposit, Fair Value	828,415	753,483
Other borrowings, Fair Value	23,662	24,604
Subordinated debentures, Fair Value	0	0
Significant Other Observable Inputs (Level 2) \| U.S. Treasury and U.S. government agencies
Financial Assets:
Fair Value	21,599	18,965
Significant Other Observable Inputs (Level 2) \| Mortgage-backed securities, residential
Financial Assets:
Fair Value	339,711	364,976
Significant Other Observable Inputs (Level 2) \| Collateralized mortgage obligations, residential
Financial Assets:
Fair Value	13,317	14,089
Significant Other Observable Inputs (Level 2) \| Mortgage-backed securities, multifamily
Financial Assets:
Fair Value	4,066	2,734
Significant Other Observable Inputs (Level 2) \| Obligations of states and political subdivisions
Financial Assets:
Fair Value	434,685	410,744
Significant Other Observable Inputs (Level 2) \| Corporate bonds
Financial Assets:
Fair Value	2,755	2,871
Significant Unobservable Inputs (Level 3)
Financial Assets:
Fair Value	43,795	832
Federal Home Loan Bank and other membership bank stocks, Fair Value	0	0
Fair Value	7,064,268	5,900,876
Financial Liabilities:
Certificates of deposit, Fair Value	0	0
Other borrowings, Fair Value	0	0
Subordinated debentures, Fair Value	176,848	175,243
Significant Unobservable Inputs (Level 3) \| U.S. Treasury and 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	43,795	832
Significant Unobservable Inputs (Level 3) \| Corporate bonds
Financial Assets:
Fair Value	$ 0	$ 0

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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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