Note 3 - Securities - Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Due in one year or less, available for sale, amortized cost	$ 1,101
Due in one year or less, available for sale, fair value	1,094
Due in one year or less, held to maturity, amortized cost
Due in one year or less, held to maturity, fair value
Due in over one to five years, available for sale, amortized cost	15,578
Due in over one to five years, available for sale, fair value	15,787
Due in over one to five years, held to maturity, amortized cost	6,978
Due in over one to five years, held to maturity, fair value	7,159
Due in over five to ten years, available for sale, amortized cost
Due in over five to ten years, available for sale, fair value
Due in over five to ten years, held to maturity, amortized cost	6,595
Due in over five to ten years, held to maturity, fair value	6,821
Due after ten years, available for sale, amortized cost
Due after ten years, available for sale, fair value
Due after ten years, held to maturity, amortized cost
Due after ten years, held to maturity, fair value
Agency mortgage-backed securities, residential, available for sale, amortized cost	89,625
Agency mortgage-backed securities, residential, available for sale, fair value	90,172
Agency mortgage-backed securities, residential, held to maturity, amortized cost	3
Agency mortgage-backed securities, residential, held to maturity, fair value	3
Total debt securities, available for sale, amortized cost	106,304	$ 104,867
Total debt securities, available for sale, fair value	107,053	102,164
Total debt securities, held to maturity, amortized cost	13,576	15,816
Total debt securities, held to maturity, fair value	$ 13,983	$ 16,234