Fair Value Measurements - Schedule of Carrying Amounts and Estimated Fair Values, as well as the Level Within the Fair Value Hierarchy (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 149,025	$ 115,921	$ 133,837	$ 83,876
Available for sale debt securities	2,180,570	2,030,696
Preferred stocks and other equity securities	88,476	90,107
FHLB and other bank stock	58,184	56,881
Loans held for sale	4,167	12,736
Bank-owned life insurance	212,925	201,069
Derivative assets	15,352
Deposits	9,486,276	8,673,927
Advances from the FHLB and other borrowings	753,921	749,113
Derivative liabilities	16,839
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	149,025	115,921
Available for sale debt securities	2,180,570	2,030,696
Preferred stocks and other equity securities	88,476	90,107
FHLB and other bank stock	58,184	56,881
Loans, net	8,655,179	7,930,639
Loans held for sale	4,167	12,736
Bank-owned life insurance	212,925	201,069
Derivative assets	15,352	11,833
Deposits	9,486,276	8,673,927
Advances from the FHLB and other borrowings	753,921	749,113
Derivative liabilities	16,839	11,833
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	149,025	115,921
Available for sale debt securities	2,180,570	2,130,696
Preferred stocks and other equity securities	88,476	90,107
FHLB and other bank stock	58,184	56,881
Loans, net	8,584,396	7,877,094
Loans held for sale	4,167	12,736
Bank-owned life insurance	212,925	201,069
Derivative assets	15,352	11,833
Deposits	9,471,692	8,664,125
Advances from the FHLB and other borrowings	744,342	740,941
Derivative liabilities	16,839	11,833
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	149,025	115,921
Available for sale debt securities	56,321	55,970
Preferred stocks and other equity securities	12,754	12,954
FHLB and other bank stock	0	0
Loans, net	0	0
Loans held for sale	0	0
Bank-owned life insurance	0	0
Derivative assets	0	0
Deposits	0	0
Advances from the FHLB and other borrowings	0	0
Derivative liabilities	0	0
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Available for sale debt securities	2,124,249	1,974,726
Preferred stocks and other equity securities	75,722	77,153
FHLB and other bank stock	58,184	56,881
Loans, net	0	0
Loans held for sale	4,167	12,736
Bank-owned life insurance	212,925	201,069
Derivative assets	15,352	11,833
Deposits	9,471,692	8,664,125
Advances from the FHLB and other borrowings	744,342	740,941
Derivative liabilities	16,839	11,833
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Available for sale debt securities	0	0
Preferred stocks and other equity securities	0	0
FHLB and other bank stock	0	0
Loans, net	8,584,396	7,877,094
Loans held for sale	0	0
Bank-owned life insurance	0	0
Derivative assets	0	0
Deposits	0	0
Advances from the FHLB and other borrowings	0	0
Derivative liabilities	$ 0	$ 0

Equity Securities, FV-NI

No definition available.

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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The carrying amount of a life insurance policy on an officer, executive or employee for which the reporting entity (a bank) is entitled to proceeds from the policy upon death of the insured or surrender of the insurance policy.

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Sum of the carrying values as of the balance sheet date of all debt, including all short-term borrowings, long-term debt, and capital lease obligations.

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Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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The aggregate of all deposit liabilities held by the entity, including foreign and domestic, interest and noninterest bearing; may include demand deposits, saving deposits, Negotiable Order of Withdrawal (NOW) and time deposits among others.

+ References

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Fair value portion of deposit liabilities held by the entity, including, but not limited to, foreign and domestic, interest and noninterest bearing, demand deposits, saving deposits, negotiable orders of withdrawal (NOW) and time deposits.

+ References

No definition available.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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- Definition

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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No definition available.

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Amount of Federal Home Loan Bank (FHLB) and Federal Reserve Bank stock.

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No definition available.

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

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No definition available.

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Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

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Amount, after allowance for bad debt, of loan receivables held-for-sale that are not part of a disposal group. Excludes loans and leases covered under loss sharing agreements and loans classified as debt securities.

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