Note 18 - Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis (Details) - Fair Value, Measurements, Nonrecurring [Member] - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Impaired loans	$ 5,836,000	$ 9,896,000
Foreclosed assets	2,260,000	469,000
Total	8,096,000	10,365,000
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	5,836,000	9,896,000
Foreclosed assets	2,260,000	469,000
Total	$ 8,096,000	$ 10,365,000