Fair Value of Financial Instruments - Summary of Estimated Fair Values of Financial Instruments (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Assets
Cash and due from banks	$ 83,721	$ 48,650
Investment securities, held to maturity	187,027	187,629
Loans held for sale	7,369	7,917
Loans excluding loan level hedges, net	2,183,138	1,739,713
Stock in FHLB and FRB	20,877	13,823
Interest receivable	12,702	10,535
Liabilities
Non-interest bearing deposits	479,771	335,955
Interest-bearing deposits	1,856,391	1,544,198
Borrowings	569,908	449,347
Subordinated debentures	37,418	32,797
Interest payable	1,015	507
Carrying Amount [Member]
Assets
Cash and due from banks	83,721	48,650
Investment securities, held to maturity	187,027	187,629
Loans held for sale	7,369	7,917
Loans excluding loan level hedges, net	2,062,437	1,619,125
Stock in FHLB and FRB	20,877	13,823
Interest receivable	12,702	10,535
Liabilities
Non-interest bearing deposits	479,771	335,955
Interest-bearing deposits	1,856,391	1,544,198
Borrowings	569,908	449,347
Subordinated debentures	37,418	32,797
Interest payable	1,015	507
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets
Cash and due from banks	83,721	48,650
Liabilities
Non-interest bearing deposits	479,771	335,955
Significant Other Observable Inputs (Level 2) [Member]
Assets
Investment securities, held to maturity	194,294	193,703
Stock in FHLB and FRB	20,877	13,823
Interest receivable	12,702	10,535
Liabilities
Interest-bearing deposits	1,873,377	1,461,314
Borrowings	566,880	441,547
Subordinated debentures	36,491	32,996
Interest payable	1,015	507
Significant Unobservable Inputs (Level 3) [Member]
Assets
Loans held for sale	7,369	7,917
Loans excluding loan level hedges, net	$ 2,046,807	$ 1,703,506

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For banks and other depository institutions: Includes cash on hand (currency and coin), cash items in process of collection, noninterest bearing deposits due from other financial institutions (including corporate credit unions), and noninterest bearing balances with the Federal Reserve Banks, Federal Home Loan Banks and central banks.

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

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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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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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