Fair Value - Carrying Amount and Fair Value of Financial Instruments (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
ASSETS
Cash and cash equivalents	$ 29,183	$ 27,261	$ 27,928	$ 29,633
Securities available for sale	495,835	546,043
Trading securities	4,858	4,576
Loans held for sale	7,528	1,381
Net loans	1,857,206	1,561,061
FHLB and other equity interests	19,186	15,921
Liabilities
Deposits	(2,017,522)	(1,815,053)
Subordinated debentures	(70,620)	(20,620)
Deposits held for sale	(6,456)	0
Carrying Amount [Member]
ASSETS
Cash and cash equivalents	29,183	27,261
Securities available for sale	495,835	546,043
Trading securities	4,858	4,576
Loans held for sale	7,528	1,381
Net loans	1,857,206	1,561,061
FHLB and other equity interests	19,186	15,921
Interest rate swaps	211	131
Accrued interest receivable	8,264	7,312
Liabilities
Deposits	(2,017,522)	(1,815,053)
FHLB and other borrowings	(237,004)	(220,515)
Subordinated debentures	(70,620)	(20,620)
Deposits held for sale	(6,456)
Interest rate swaps	(670)	(867)
Accrued interest payable	(510)	(766)
Total Fair Value [Member]
ASSETS
Cash and cash equivalents	29,183	27,261
Securities available for sale	495,835	546,043
Trading securities	4,858	4,576
Loans held for sale	7,553	1,438
Net loans	1,817,341	1,554,502
Interest rate swaps	211	131
Accrued interest receivable	8,264	7,312
Liabilities
Deposits	(2,006,513)	(1,813,916)
FHLB and other borrowings	(226,769)	(218,808)
Subordinated debentures	(61,831)	(11,761)
Deposits held for sale	(6,417)
Interest rate swaps	(670)	(867)
Accrued interest payable	(510)	(766)
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
ASSETS
Cash and cash equivalents	29,183	27,261
Securities available for sale	971	981
Trading securities	4,805	4,522
Loans held for sale	0	0
Net loans	0	0
Interest rate swaps	0	0
Accrued interest receivable	6	5
Liabilities
Deposits	(1,786,748)	(1,630,888)
FHLB and other borrowings	0	0
Subordinated debentures	0	0
Deposits held for sale	0
Interest rate swaps	0	0
Accrued interest payable	0	(344)
Significant Other Observable Inputs (Level 2) [Member]
ASSETS
Cash and cash equivalents	0	0
Securities available for sale	492,815	541,649
Trading securities	53	54
Loans held for sale	7,553	1,438
Net loans	0	0
Interest rate swaps	211	131
Accrued interest receivable	3,014	2,875
Liabilities
Deposits	(219,765)	(183,028)
FHLB and other borrowings	(226,769)	(218,808)
Subordinated debentures	(61,831)	(11,761)
Deposits held for sale	(6,417)
Interest rate swaps	(670)	(867)
Accrued interest payable	(510)	(422)
Significant Unobservable Inputs (Level 3) [Member]
ASSETS
Cash and cash equivalents	0	0
Securities available for sale	2,049	3,413
Trading securities	0	0
Loans held for sale	0	0
Net loans	1,817,341	1,554,502
Interest rate swaps	0	0
Accrued interest receivable	5,244	4,432
Liabilities
Deposits	0	0
FHLB and other borrowings	0	0
Subordinated debentures	0	0
Deposits held for sale	0
Interest rate swaps	0	0
Accrued interest payable	$ 0	$ 0

Deposits held for sale.

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Federal home loan bank treasury tax and loan and other borrowings.

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

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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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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.

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Amount of interest payable on debt, including, but not limited to, trade payables.

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Fair value as of the balance sheet date of interest rate derivative assets, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as assets.

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Carrying amount as of the balance sheet date of interest earned but not received. Also called accrued interest or accrued interest receivable.

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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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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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Includes other investments and securities that are not at fair value as of the balance sheet date and those that are not accounted for under the equity method.

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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 investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.

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