Note 9 - Fair Value Measurement - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale	$ 204,656	$ 179,613
Fair Value, Recurring [Member]
Assets, Fair Value Disclosure	205,465	179,754
Fair Value, Recurring [Member] | Interest Rate Swap [Member]
Interest rate swaps	809	141
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure	205,465	179,754
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Interest Rate Swap [Member]
Interest rate swaps	809	141
Residential Mortgage Backed Securities Issued by US Government Sponsored Enterprises [Member]
Debt Securities, Available-for-sale	120,395	110,674
Residential Mortgage Backed Securities Issued by US Government Sponsored Enterprises [Member] | Fair Value, Recurring [Member]
Debt Securities, Available-for-sale	120,395	110,674
Residential Mortgage Backed Securities Issued by US Government Sponsored Enterprises [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Debt Securities, Available-for-sale	120,395	110,674
Commercial Mortgage Backed Securities Issued by US Government Agencies [Member]
Debt Securities, Available-for-sale	19,873
Commercial Mortgage Backed Securities Issued by US Government Agencies [Member] | Fair Value, Recurring [Member]
Debt Securities, Available-for-sale	19,873	10,472
Commercial Mortgage Backed Securities Issued by US Government Agencies [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Debt Securities, Available-for-sale	19,873	10,472
US States and Political Subdivisions Debt Securities [Member]
Debt Securities, Available-for-sale	64,388	58,467
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Recurring [Member]
Debt Securities, Available-for-sale	64,388	58,467
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Debt Securities, Available-for-sale	$ 64,388	$ 58,467