Note 11 - Assets and Liabilities Measured and Reported at Fair Value - Assets Measured at Fair Value on a Non-recurring Basis (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Other real estate owned			$ (0)	$ 63
Fair Value, Nonrecurring [Member]
Collateral dependent loans	$ 0		0
Collateral dependent loans	0		0
Other real estate owned	0		0		$ 0
Other real estate owned	0	$ 0	0	0
Impaired loans					0
Impaired loans		$ 0		$ 0
Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 1 [Member]
Collateral dependent loans	0		0
Other real estate owned	0		0		0
Impaired loans					0
Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member]
Collateral dependent loans	8,278		8,278
Other real estate owned	612		612		493
Impaired loans					7,253
Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Collateral dependent loans	8,278		8,278
Other real estate owned	$ 612		$ 612		493
Impaired loans					$ 7,253