Note 3 - Debt Securities - Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Securities available for sale, due within one year, amortized cost	$ 0
Securities available for sale, due after one year but within five years, amortized cost	24,485
Securities available for sale, due after five years but within ten years, amortized cost	20,020
Securities available for sale, due after ten years, amortized cost	0
Securities available for sale, single maturity date, amortized cost	44,505
Securities available for sale, amortized cost	81,958	$ 168,478
Securities available for sale, due within one year, fair value	0
Securities available for sale, due after one year but within five years, fair value	24,703
Securities available for sale, due after five years but within ten years, fair value	20,307
Securities available for sale, due after ten years, fair value	0
Securities available for sale, single maturity date, fair value	45,010
Securities available for sale	83,358	169,574
US Government Agencies Debt Securities [Member]
Securities available for sale, due within one year, amortized cost	0
Securities available for sale, due after one year but within five years, amortized cost	0
Securities available for sale, due after five years but within ten years, amortized cost	555
Securities available for sale, due after ten years, amortized cost	0
Securities available for sale, single maturity date, amortized cost	555
Securities available for sale, amortized cost	555	5,038
Securities available for sale, due within one year, fair value	0
Securities available for sale, due after one year but within five years, fair value	0
Securities available for sale, due after five years but within ten years, fair value	551
Securities available for sale, due after ten years, fair value	0
Securities available for sale, single maturity date, fair value	551
Securities available for sale	551	5,034
US States and Political Subdivisions Debt Securities [Member]
Securities available for sale, due within one year, amortized cost	0
Securities available for sale, due after one year but within five years, amortized cost	24,485
Securities available for sale, due after five years but within ten years, amortized cost	19,465
Securities available for sale, due after ten years, amortized cost	0
Securities available for sale, single maturity date, amortized cost	43,950
Securities available for sale, amortized cost	43,950	85,992
Securities available for sale, due within one year, fair value	0
Securities available for sale, due after one year but within five years, fair value	24,703
Securities available for sale, due after five years but within ten years, fair value	19,756
Securities available for sale, due after ten years, fair value	0
Securities available for sale, single maturity date, fair value	44,459
Securities available for sale	44,459	$ 86,878
Collateralized Mortgage Backed Securities [Member]
Securities available for sale, no single maturity date, amortized cost	37,453
Securities available for sale, no single maturity date, fair value	$ 38,348

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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