Note 5 - Mortgage Loan Servicing (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Continuing Involvement with Transferred Financial Assets Custodial Escrow Balance	$ 11,800	$ 6,400
Valuation Allowance for Impairment of Recognized Servicing Assets, Balance, Ending Balance	0	0
Servicing Asset at Fair Value, Amount, Ending Balance	$ 10,000	$ 7,400
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Discount Rate	7.75%	10.00%
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Prepayment Speed	14.00%	15.30%
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Expected Credit Losses	0.40%	0.32%
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Weighted Average Life (Year)	6 years 1 month 6 days	5 years 3 months 18 days