Note 12 - Fair Value Measurements - Balances of Assets Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Fair value, available for sale securities	$ 123,193	$ 120,983
Total liabilities	31
Fair Value, Inputs, Level 1 [Member]
Fair value, available for sale securities	0	0
Total liabilities	0
Fair Value, Inputs, Level 2 [Member]
Fair value, available for sale securities	123,193	120,983
Total liabilities	31
Fair Value, Inputs, Level 3 [Member]
Fair value, available for sale securities	0	0
Total liabilities	0
Fair Value, Recurring [Member]
Derivatives - cash flow hedges	31
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Derivatives - cash flow hedges	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Derivatives - cash flow hedges	31
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Derivatives - cash flow hedges	0
US Agency and Mortgage-backed Securities [Member]
Fair value, available for sale securities	94,820	94,905
US Agency and Mortgage-backed Securities [Member] | Fair Value, Recurring [Member]
Fair value, available for sale securities	94,820	94,905
US Agency and Mortgage-backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value, available for sale securities	0	0
US Agency and Mortgage-backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair value, available for sale securities	94,820	94,905
US Agency and Mortgage-backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value, available for sale securities	0	0
Municipal Bonds [Member]
Fair value, available for sale securities	28,373	26,078
Municipal Bonds [Member] | Fair Value, Recurring [Member]
Fair value, available for sale securities	28,373	26,078
Municipal Bonds [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value, available for sale securities	0	0
Municipal Bonds [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair value, available for sale securities	28,373	26,078
Municipal Bonds [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value, available for sale securities	$ 0	$ 0