Note 7 - Fair Value - Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($)	Sep. 30, 2020	Dec. 31, 2019
Securities - available-for-sale	$ 99,652,000	$ 120,107,000
Securities - equity investments	12,000	19,000
Fair Value, Inputs, Level 1 [Member]
Securities - available-for-sale
Securities - equity investments	12,000	19,000
Fair Value, Inputs, Level 2 [Member]
Securities - available-for-sale	96,130,000	116,085,000
Securities - equity investments
Fair Value, Inputs, Level 3 [Member]
Securities - available-for-sale	3,522,000	4,022,000
Securities - equity investments
US Government-sponsored Enterprises Debt Securities [Member]
Securities - available-for-sale	1,017,000	7,077,000
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	1,017,000	7,077,000
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	19,692,000	41,075,000
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	19,692,000	41,075,000
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	20,859,000	32,837,000
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	20,859,000	32,837,000
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	45,561,000	27,796,000
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	45,561,000	27,796,000
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	12,523,000	11,322,000
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	9,001,000	7,300,000
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Securities - available-for-sale	$ 3,522,000	$ 4,022,000