Note 6 - Mortgage Loan Servicing (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Continuing Involvement with Transferred Financial Assets Custodial Escrow Balance	$ 4,100	$ 4,700
Valuation Allowance for Impairment of Recognized Servicing Assets, Balance, Ending Balance	0	0
Servicing Asset at Fair Value, Amount, Ending Balance	$ 8,400	$ 8,400
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Discount Rate	10.00%	7.50%
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Prepayment Speed	9.30%	11.80%
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Expected Credit Losses	0.32%	0.73%
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Weighted Average Life	7 years 109 days	3 years 146 days