Note 3 - Securities - Expected Maturities of Investment Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Available-for-sale securities, amortized cost, one year or less	$ 110
Available-for-sale securities, fair value, one year or less	112
Available-for-sale securities, amortized cost, after one year through five years	84,710
Available-for-sale securities, fair value, after one year through five years	83,229
Available-for-sale securities, amortized cost, after five years through ten years	88,333
Available-for-sale securities, fair value, after five years through ten years	86,912
Available-for-sale securities, amortized cost, after ten years	86,659
Available-for-sale securities, fair value, after ten years	85,664
Available-for-sale securities, amortized cost, total	259,812	$ 268,406
Available-for-sale securities, fair value, total	$ 255,917

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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

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