Note 11 - Fair Values - Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis (Details) - Fair Value, Measurements, Nonrecurring [Member] - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Impaired loans	$ 9,192,000	$ 5,836,000
Foreclosed assets	948,000	2,260,000
Total	10,140,000	8,096,000
Fair Value, Inputs, Level 1 [Member]
Impaired loans	0	0
Foreclosed assets	0	0
Total	0	0
Fair Value, Inputs, Level 2 [Member]
Impaired loans	0	0
Foreclosed assets	0	0
Total	0	0
Fair Value, Inputs, Level 3 [Member]
Impaired loans	9,192,000	5,836,000
Foreclosed assets	948,000	2,260,000
Total	$ 10,140,000	$ 8,096,000