Note 15 - Fair Values of Financial Instruments - Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Securities - available-for-sale	$ 120,107,000	$ 97,718,000
Securities - equity investments	19,000	7,000
Fair Value, Inputs, Level 1 [Member]
Securities - available-for-sale		4,445,000
Securities - equity investments	19,000	7,000
Fair Value, Inputs, Level 2 [Member]
Securities - available-for-sale	115,857,000	89,773,000
Securities - equity investments
Fair Value, Inputs, Level 3 [Member]
Securities - available-for-sale	4,250,000	3,500,000
Securities - equity investments
US Government-sponsored Enterprises Debt Securities [Member]
Securities - available-for-sale	7,077,000	16,783,000
US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities - available-for-sale
US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities - available-for-sale	7,077,000	16,783,000
US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Securities - available-for-sale
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Securities - available-for-sale	41,075,000	27,176,000
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Fair Value, Inputs, Level 1 [Member]
Securities - available-for-sale
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Fair Value, Inputs, Level 2 [Member]
Securities - available-for-sale	41,075,000	27,176,000
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Fair Value, Inputs, Level 3 [Member]
Securities - available-for-sale
Collateralized Mortgage Obligations [Member]
Securities - available-for-sale	32,837,000	18,664,000
Collateralized Mortgage Obligations [Member] | Fair Value, Inputs, Level 1 [Member]
Securities - available-for-sale
Collateralized Mortgage Obligations [Member] | Fair Value, Inputs, Level 2 [Member]
Securities - available-for-sale	32,837,000	18,664,000
Collateralized Mortgage Obligations [Member] | Fair Value, Inputs, Level 3 [Member]
Securities - available-for-sale
US States and Political Subdivisions Debt Securities [Member]
Securities - available-for-sale	27,796,000	22,732,000
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities - available-for-sale
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities - available-for-sale	27,796,000	22,732,000
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Securities - available-for-sale
Corporate Debt Securities [Member]
Securities - available-for-sale	11,322,000	7,918,000
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities - available-for-sale
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities - available-for-sale	7,072,000	4,418,000
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Securities - available-for-sale	$ 4,250,000	3,500,000
US Treasury and Government [Member]
Securities - available-for-sale		4,445,000
US Treasury and Government [Member] | Fair Value, Inputs, Level 1 [Member]
Securities - available-for-sale		4,445,000
US Treasury and Government [Member] | Fair Value, Inputs, Level 2 [Member]
Securities - available-for-sale
US Treasury and Government [Member] | Fair Value, Inputs, Level 3 [Member]
Securities - available-for-sale