Note 4 - Securities - Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Amortized cost, due in one year or less, available for sale securities	$ 8,732
Fair value, due in one year or less, available for sale securities	8,806
Amortized cost, due after one year through five years, available for sale securities	4,837
Fair value, due after one year through five years, available for sale securities	5,010
Amortized cost, due after five years through ten years, available for sale securities	130,312
Fair value, due after five years through ten years, available for sale securities	135,038
Amortized cost, due after ten years, available for sale securities	328,579
Fair value, due after ten years, available for sale securities	338,497
Amortized cost, total securities available for sale	472,460	$ 435,166
Fair value, total securities available for sale	$ 487,351	$ 435,263

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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