Note 9 - Fair Value Measurements - Assets Measured at Fair Value on a Nonrecurring Basis (Details) - Fair Value, Nonrecurring [Member] - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Jun. 30, 2020
Fair Value		$ 10,071	$ 9,403
Total Losses	$ 0	0
Fair Value, Inputs, Level 1 [Member]
Fair Value		0	0
Fair Value, Inputs, Level 2 [Member]
Fair Value		0	0
Fair Value, Inputs, Level 3 [Member]
Fair Value		10,071	9,403
Other Real Estate Owned [Member]
Fair Value		43	43
Total Losses	0	0
Other Real Estate Owned [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value		0	0
Other Real Estate Owned [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value		0	0
Other Real Estate Owned [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value		43	43
Impaired Loans [Member] | Commercial Portfolio Segment [Member]
Fair Value		5,747	5,401
Total Losses	0	0
Impaired Loans [Member] | Commercial Real Estate Portfolio Segment [Member]
Fair Value		4,091	3,773
Total Losses	0	0
Impaired Loans [Member] | Residential Portfolio Segment [Member]
Fair Value		190	186
Total Losses	$ 0	0
Impaired Loans [Member] | Fair Value, Inputs, Level 1 [Member] | Commercial Portfolio Segment [Member]
Fair Value		0	0
Impaired Loans [Member] | Fair Value, Inputs, Level 1 [Member] | Commercial Real Estate Portfolio Segment [Member]
Fair Value		0	0
Impaired Loans [Member] | Fair Value, Inputs, Level 1 [Member] | Residential Portfolio Segment [Member]
Fair Value		0	0
Impaired Loans [Member] | Fair Value, Inputs, Level 2 [Member] | Commercial Portfolio Segment [Member]
Fair Value		0	0
Impaired Loans [Member] | Fair Value, Inputs, Level 2 [Member] | Commercial Real Estate Portfolio Segment [Member]
Fair Value		0	0
Impaired Loans [Member] | Fair Value, Inputs, Level 2 [Member] | Residential Portfolio Segment [Member]
Fair Value		0	0
Impaired Loans [Member] | Fair Value, Inputs, Level 3 [Member] | Commercial Portfolio Segment [Member]
Fair Value		5,747	5,401
Impaired Loans [Member] | Fair Value, Inputs, Level 3 [Member] | Commercial Real Estate Portfolio Segment [Member]
Fair Value		4,091	3,773
Impaired Loans [Member] | Fair Value, Inputs, Level 3 [Member] | Residential Portfolio Segment [Member]
Fair Value		$ 190	$ 186