Note 8 - Fair Values - Fair Value of Assets Measured on a Non-recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Other real estate owned	$ 140	$ 35
Fair Value, Measurements, Nonrecurring [Member]
Other real estate owned	140	35
Total assets measured at fair value	140	95
Collateral dependent impaired loans		60
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 1 [Member]
Other real estate owned
Total assets measured at fair value
Collateral dependent impaired loans
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member]
Other real estate owned
Total assets measured at fair value
Collateral dependent impaired loans
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Other real estate owned	140	35
Total assets measured at fair value	$ 140	95
Collateral dependent impaired loans		$ 60