Note 8 - Deposits (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Aggregate amount of certificates of deposits, $250,000 minimum denomination	$ 169,100,000	$ 293,400,000
Minimum denomination	250,000
Prepaid brokered and public time deposits	29,200,000
Loss on prepayment of brokered and public time deposits	576,000
Prepayment of brokered certificate of deposits		0
Federal Home Loan Bank of Des Moines [Member]
FHLB advance	110,500,000	47,400,000
Amount outstanding	$ 0	$ 0