Note 7 - Fair Value Measurements - Impaired Loans and Other Real Estate Owned Measured at Fair Value on Nonrecurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Impaired loans net of valuation allowance	$ 993	$ 1,014
Other real estate owned net of valuation allowance	2,025	2,052
Fair Value, Inputs, Level 1 [Member]
Impaired loans net of valuation allowance		0
Other real estate owned net of valuation allowance	0
Fair Value, Inputs, Level 2 [Member]
Impaired loans net of valuation allowance		0
Other real estate owned net of valuation allowance	0
Fair Value, Inputs, Level 3 [Member]
Impaired loans net of valuation allowance	993	1,014
Other real estate owned net of valuation allowance	$ 2,025	$ 2,052