Note 8 - Fair Value Measurements (Details Textual) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Financial and Nonfinancial Liabilities, Fair Value Disclosure	$ 0		$ 0		$ 0
Provision for Loan and Lease Losses, Total	300,000	$ 316,000	750,000	$ 513,000
Impaired Loan [Member]
Provision for Loan and Lease Losses, Total	8,000	72,000	12,000	137,000
Foreclosed Real Estate [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Write-down or Reserve, Amount	$ 217,000	$ 419,000	$ 354,000	$ 419,000
Fair Value, Inputs, Level 3 [Member] | Impaired Loan [Member] | Minimum [Member]
Fair Value Inputs, Estimated Selling Costs			11.00%		20.00%
Fair Value, Inputs, Level 3 [Member] | Impaired Loan [Member] | Maximum [Member]
Fair Value Inputs, Estimated Selling Costs			66.00%		62.00%
Fair Value, Inputs, Level 3 [Member] | Impaired Loan [Member] | Weighted Average [Member]
Fair Value Inputs, Estimated Selling Costs			38.00%		39.00%
Fair Value, Inputs, Level 3 [Member] | Foreclosed Real Estate [Member] | Minimum [Member]
Fair Value Inputs, Estimated Selling Costs			22.00%		10.00%
Fair Value, Inputs, Level 3 [Member] | Foreclosed Real Estate [Member] | Maximum [Member]
Fair Value Inputs, Estimated Selling Costs			73.00%		79.00%
Fair Value, Inputs, Level 3 [Member] | Foreclosed Real Estate [Member] | Weighted Average [Member]
Fair Value Inputs, Estimated Selling Costs			24.00%		51.00%