Note 3 - Securities - Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Sep. 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	1,096
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	15,476
Due in over one to five years, available for sale, fair value	15,640
Due in over one to five years, held to maturity, amortized cost	6,580
Due in over one to five years, held to maturity, fair value	6,745
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	6,902
Due in over five to ten years, held to maturity, fair value	7,135
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	94,168
Agency mortgage-backed securities, residential, available for sale, fair value	94,506
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	110,745	$ 104,867
Total debt securities, available for sale, fair value	111,242	102,164
Total debt securities, held to maturity, amortized cost	13,485	15,816
Total debt securities, held to maturity, fair value	$ 13,883	$ 16,234