Note 8 - Fair Value - Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Securities-available for sale	$ 97,509,000	$ 99,350,000
Securities-equity investments	473,000	1,817,000
Fair Value, Inputs, Level 1 [Member]
Securities-available for sale	4,395,000	4,472,000
Securities-equity investments	473,000	1,683,000
Fair Value, Inputs, Level 2 [Member]
Securities-available for sale	89,614,000	86,880,000
Securities-equity investments
Fair Value, Inputs, Level 3 [Member]
Securities-available for sale	3,500,000	7,998,000
Securities-equity investments		134,000
US Treasury and Government [Member]
Securities-available for sale	4,395,000	4,472,000
US Treasury and Government [Member] | Fair Value, Inputs, Level 1 [Member]
Securities-available for sale	4,395,000	4,472,000
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
US Government-sponsored Enterprises Debt Securities [Member]
Securities-available for sale	16,550,000	13,926,000
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	16,550,000	13,926,000
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	27,664,000	20,758,000
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	27,664,000	20,758,000
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	19,205,000	21,924,000
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	19,205,000	21,924,000
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	22,260,000	29,240,000
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	22,260,000	29,240,000
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	7,435,000	9,030,000
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	3,935,000	1,032,000
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Securities-available for sale	$ 3,500,000	$ 7,998,000