Note 3 - Investment Securities - Amortized Cost and Fair Value of Debt Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Due in one year or less, amortized cost	$ 69
Due in one year or less	70
Due after one year through five years, amortized cost	5,176
Due after one year through five years	5,298
Due after five years through ten years, amortized cost	2,146
Due after five years through ten years	2,295
Due after ten years, amortized cost	82,347
Due after ten years	86,383
Total, amortized cost	89,738
Total	94,046
U.S. Government-sponsored mortgage-backed and related securities, amortized cost	72,436
U.S. Government-sponsored mortgage-backed and related securities	73,531
Total investment securities available-for-sale, amortized cost	162,174	$ 134,731
Total investment securities available-for-sale	$ 167,577	$ 136,131