Note 4 -Pooled Trust Preferred Securities (Details) $ in Thousands	12 Months Ended
Dec. 31, 2017 USD ($) bank InsuranceCompany	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, amortized cost	$ 385,736	$ 396,168
Fair value	379,545	390,475
Total recognized OTTI credit loss	$ (80)	$ (192)	$ (55)
PreTSL IV [Member]
Schedule Of Available For Sale Securities [Line Items]
Class	Mezzanine*
Investment securities available-for-sale, amortized cost	$ 241
Fair value	215
Unrealized gains (losses)	(26)
Realized OTTI credit loss	(1)
Total recognized OTTI credit loss	$ (1)
Moody's/Fitch ratings	Ba1/BB
Current number of performing banks \| bank	5
Current number of performing insurance companies \| InsuranceCompany	0
Actual deferrals and defaults as a % of total collateral	18.00%
Total performing collateral as a % of outstanding bonds	143.00%

Class of pooled trust preferred security owned.

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Current number of performing banks.

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Current number of performing insurance companies.

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

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Description of the credit rating indicative of likelihood of repayment of the debt instrument given by a credit rating agency (for example, Standard and Poor's, Moody's, Fitch).

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The amount by which the fair value of an investment is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

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The amount by which the fair value of an investment in debt and equity securities categorized as Available-for-sale is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

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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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Amount of unrealized gain (loss) recognized in the income statement on unsold other securities.

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