Note 9 - Fair Values - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Securities available-for-sale	$ 285,077	$ 286,950
Fair Value, Recurring [Member]
Total assets measured at fair value	285,077	286,950
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Total assets measured at fair value
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Total assets measured at fair value	285,077	286,950
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Total assets measured at fair value
US Government Agencies Debt Securities [Member]
Securities available-for-sale	36,043	38,733
US Government Agencies Debt Securities [Member] | Fair Value, Recurring [Member]
Securities available-for-sale	36,043	38,733
US Government Agencies Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
US Government Agencies Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale	36,043	38,733
US Government Agencies Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
US States and Political Subdivisions Debt Securities [Member]
Securities available-for-sale	63,263	42,098
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Recurring [Member]
Securities available-for-sale	63,263	42,098
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale	63,263	42,098
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Residential Mortgage Backed Securities and Collateralized Mortgage Obligations [Member]
Securities available-for-sale	160,439	180,835
Residential Mortgage Backed Securities and Collateralized Mortgage Obligations [Member] | Fair Value, Recurring [Member]
Securities available-for-sale	160,439	180,835
Residential Mortgage Backed Securities and Collateralized Mortgage Obligations [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Residential Mortgage Backed Securities and Collateralized Mortgage Obligations [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale	160,439	180,835
Residential Mortgage Backed Securities and Collateralized Mortgage Obligations [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Corporate Debt Securities [Member]
Securities available-for-sale	2,983	2,966
Corporate Debt Securities [Member] | Fair Value, Recurring [Member]
Securities available-for-sale	2,983	2,966
Corporate Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Corporate Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale	2,983	2,966
Corporate Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Commercial Mortgage Backed Securities [Member]
Securities available-for-sale	17,428	19,307
Commercial Mortgage Backed Securities [Member] | Fair Value, Recurring [Member]
Securities available-for-sale	17,428	19,307
Commercial Mortgage Backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Commercial Mortgage Backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale	17,428	19,307
Commercial Mortgage Backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Asset-backed Securities [Member]
Securities available-for-sale	4,921	3,011
Asset-backed Securities [Member] | Fair Value, Recurring [Member]
Securities available-for-sale	4,921	3,011
Asset-backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Asset-backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale	4,921	3,011
Asset-backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale