Note 8 - Fair Value - Quantitative Information for Financial Instruments on Non-recurring Basis (Details) - Real Estate Portfolio [Member] - Nonresidential Real Estate [Member] - Fair Value, Nonrecurring [Member] $ in Thousands	Sep. 30, 2020 USD ($)
Impaired loans, fair value	$ 268
Fair Value, Inputs, Level 3 [Member]
Impaired loans, fair value	$ 268
Fair Value, Inputs, Level 3 [Member] | Valuation, Market Approach [Member] | Measurement Input, Discount Rate [Member]
Imapired loans, measurement input	0.220