Note 11 - Fair Value Measurements (Details) - Fair Values of Financial Instruments - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014
Assets
Cash and due from banks, carrying value	$ 10,703	$ 9,097	$ 7,920
Cash and due from banks, fair value	10,703	9,097
Federal funds sold, carrying value	4,076	3,516	8,968
Federal funds sold, fair value	4,076	3,516	8,968
Interest bearing deposits with other banks, carrying value	291,276	243,412	191,468
Interest bearing deposits with other banks, fair value	291,276	243,412	191,468
Investment securities, carrying value	524,326	382,343	382,468
Investment securities, fair value	524,326	382,343	382,468
Federal Reserve and Federal Home Loan Bank stock, carrying value	16,865	22,560
Federal Reserve and Federal Home Loan Bank stock, fair value	16,865	22,560
Loans held for sale, carrying value	35,713	44,317	41,254
Loans held for sale, fair value	35,713	44,669
Loans, carrying value	4,776,965	4,312,399	3,432,548
Loans, fair value	4,778,753	4,314,618
Bank owned life insurance, carrying value	58,284	56,594	40,432
Bank owned life insurance, fair value	58,284	56,594	40,432
Annuity investment, carrying value	12,137	11,277
Annuity investment, fair value	12,137	11,277
derivatives-asset, carrying value	3,445
derivatives-asset, fair value	3,445
Liabilities
Noninterest bearing deposits	4,926,588	4,310,768	$ 3,533,850
Certificates of deposit	802,115	688,741
Certificates of deposit	802,449	688,067
Customer repurchase agreements	64,893	61,120
Customer repurchase agreements	64,893	61,120
Borrowings, carrying value	70,000	219,300
Borrowings, fair value	70,000	220,838
Mortgage banking derivatives-liabilities	245	250
Mortgage Banking Derivative [Member]
Assets
derivatives-asset, carrying value	197	146
derivatives-asset, fair value	197	146
Noninterest-bearing Deposits [Member]
Liabilities
Noninterest bearing deposits	1,402,447	1,175,799
Noninterest bearing deposits	1,402,447	1,175,799
Interest-bearing Deposits [Member]
Liabilities
Noninterest bearing deposits	2,722,026	2,446,228
Noninterest bearing deposits	2,722,026	2,446,228
Fair Value, Inputs, Level 1 [Member]
Assets
Investment securities, carrying value	125	198
Investment securities, fair value	125	198
Fair Value, Inputs, Level 2 [Member]
Assets
Cash and due from banks, fair value	10,703	9,097
Federal funds sold, carrying value	4,076	3,516
Federal funds sold, fair value	4,076	3,516
Interest bearing deposits with other banks, carrying value	291,276	243,412
Interest bearing deposits with other banks, fair value	291,276	243,412
Investment securities, carrying value	523,982	381,926
Investment securities, fair value	523,982	381,926
Federal Reserve and Federal Home Loan Bank stock, fair value	16,865	22,560
Loans held for sale, fair value	35,713	44,669
Loans, fair value	6,346	1,489
Bank owned life insurance, carrying value	58,284	56,594
Bank owned life insurance, fair value	58,284	56,594
Annuity investment, fair value	12,137	11,277
derivatives-asset, fair value	3,445
Liabilities
Certificates of deposit	802,449	688,067
Customer repurchase agreements	64,893	61,120
Borrowings, fair value	70,000	220,838
Fair Value, Inputs, Level 2 [Member] \| Noninterest-bearing Deposits [Member]
Liabilities
Noninterest bearing deposits	1,402,447	1,175,799
Fair Value, Inputs, Level 2 [Member] \| Interest-bearing Deposits [Member]
Liabilities
Noninterest bearing deposits	2,722,026	2,446,228
Fair Value, Inputs, Level 3 [Member]
Assets
Investment securities, carrying value	219	219
Investment securities, fair value	219	219
Loans, fair value	4,772,407	4,313,129
Liabilities
Mortgage banking derivatives-liabilities	245	250
Fair Value, Inputs, Level 3 [Member] \| Mortgage Banking Derivative [Member]
Assets
derivatives-asset, fair value	$ 197	$ 146

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An agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified price.

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An agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified fair value price.

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Fair value amount of deposits that cannot be withdrawn before a set date without penalty or for which notice of withdrawal is required. Time deposits include, but are not limited to, certificates of deposits, individual retirement accounts and open accounts.

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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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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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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 portion of the amount that could be realized under a life insurance contract or contracts owned by the entity, commonly known as corporate-owned life insurance (COLI) or bank-owned life insurance (BOLI).

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Carrying amount as of the balance sheet date of amounts which could be received based on the terms of the insurance contract upon surrendering life policies owned by the entity.

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The carrying amount of the asset transferred to a third party to serve as a deposit, which typically serves as security against failure by the transferor to perform under terms of an agreement.

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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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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.

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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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The amount outstanding of funds lent to other depository institutions, securities brokers, or securities dealers in the form of Federal Funds sold; for example, immediately available funds lent under agreements or contracts that mature in one business day or roll over under a continuing contract, regardless of the nature of the transaction or the collateral involved, excluding overnight lending for commercial and industrial purposes. Also include Federal Funds sold under agreements to resell on a gross basis, excluding (1) sales of term Federal Funds, (2) due bills representing purchases of securities or other assets by the reporting bank that have not yet been delivered and similar instruments, (3) resale agreements that mature in more than one business day involving assets other than securities, and (4) yield maintenance dollar repurchase agreements.

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For banks and other depository institutions (including Federal Reserve Banks, if applicable): Interest-bearing deposits in other financial institutions for relatively short periods of time including, for example, certificates of deposits, which are presented separately from cash on the balance sheet.

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Amount before allowance and after 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.

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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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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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Fair value portion of other liabilities.

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Investments which are not defined as or included in marketable (debt, equity, or other) securities whose use is restricted in whole or in part, generally by contractual agreements or regulatory requirements. For use in an unclassified balance sheet.

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The aggregate value of all restricted investments.

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Amount of deposits that cannot be withdrawn before a set date without penalty or for which notice of withdrawal is required. Time deposits include, but are not limited to, certificates of deposits, individual retirement accounts and open accounts.

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