Note 2 - Investment Securities - Amortized Cost and Fair Value of Debt Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Securities available for sale, amortized cost, due in one year or less	$ 19,508
Securities available for sale, fair value, due in one year or less	19,588
Securities available for sale, amortized cost, due after one year through five years	87,758
Securities available for sale, fair value, due after one year through five years	88,430
Securities available for sale, amortized cost, due after five years through ten years	39,063
Securities available for sale, fair value, due after five years through ten years	40,371
Securities available for sale, amortized cost, due after ten years	79,956
Securities available for sale, fair value, due after ten years	81,530
Securities available for sale, amortized cost, single maturity	226,285
Securities available for sale, fair value, single maturity	229,919
Mortgage-backed securities and CMO, amortized cost	82,350
Mortgage-backed securities and CMO, fair value	83,621
Securities available for sale, amortized cost	308,635	$ 274,709
Securities available for sale, fair value	$ 313,540	$ 283,502

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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