Fair Value Measurement and Fair Value of Financial Instruments - Carrying Values and Fair Values of Company's Financial Instruments (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Financial Assets:
Investment securities held to maturity, Fair Value	$ 150,932	$ 138,688
Investment securities held to maturity, Carrying Value	153,646	139,685
Federal Home Loan Bank and other membership bank stocks, Fair Value	13,301	12,576
Federal Home Loan Bank and other membership bank stocks, Carrying Value	13,301	12,576
Loans and leases, net Fair Value	4,341,477	4,114,516
Loans and leases, net Carrying Value	4,419,045	4,117,265
Financial Liabilities:
Certificates of deposit, Fair Value	750,801	732,417
Certificates of deposit, Carrying value	757,038	737,428
Other borrowings, Fair Value	176,921	189,080
Other borrowings, Carrying value	181,118	192,011
Subordinated debentures, Fair Value	102,497	97,244
Subordinated debentures, Carrying Value	105,027	104,902
Significant Other Observable Inputs (Level 2)
Financial Assets:
Investment securities held to maturity, Fair Value	143,913	127,901
Federal Home Loan Bank and other membership bank stocks, Fair Value	13,301	12,576
Financial Liabilities:
Certificates of deposit, Fair Value	750,801	732,417
Other borrowings, Fair Value	176,921	189,080
Significant Unobservable Inputs (Level 3)
Financial Assets:
Investment securities held to maturity, Fair Value	7,019	10,787
Loans and leases, net Fair Value	4,341,477	4,114,516
Financial Liabilities:
Subordinated debentures, Fair Value	$ 102,497	$ 97,244

Certificate of deposits fair value disclosure.

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Loans And Leases Receivable Fair Value Disclosure

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Other Borrowings Fair Value Disclosure

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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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Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

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Fair value of investments in debt securities classified as held-to-maturity.

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

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

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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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Including the current and noncurrent portions, carrying value as of the balance sheet date of subordinated debt (with initial maturities beyond one year or beyond the operating cycle if longer). Subordinated debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets.

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Amount of time deposit liabilities, including certificates of deposit.

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