Note 3 - Loans and Allowance for Loan Losses - Activity for Troubled Debt Restructurings (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Beginning Balance	$ 8,587,000	$ 14,138,000	$ 3,990,000
Charge-Offs	0	0	(505,000)
Payments	(11,260,000)	(20,364,000)	(792,000)
Transfers to ORE	0	0	0
Net Additions/Deletions	9,087,000	14,813,000	11,445,000
Ending Balance	6,414,000	8,587,000	14,138,000
Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Beginning Balance	85,000	0	383,000
Charge-Offs	0	0	0
Payments	(85,000)	(2,000)	(383,000)
Transfers to ORE	0	0	0
Net Additions/Deletions	0	87,000	0
Ending Balance	0	85,000	0
Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Beginning Balance	1,145,000	3,100,000	2,026,000
Charge-Offs	0	0	0
Payments	(3,765,000)	(3,820,000)	(6,663,000)
Transfers to ORE	0	(97,000)	(93,000)
Net Additions/Deletions	17,417,000	1,962,000	7,830,000
Ending Balance	14,797,000	1,145,000	3,100,000
Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Beginning Balance	178,000	210,000	237,000
Charge-Offs	0	0	0
Payments	(585,000)	(32,000)	(27,000)
Transfers to ORE	0	0	0
Net Additions/Deletions	887,000	0	0
Ending Balance	480,000	178,000	210,000
Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Beginning Balance	7,000	24,000	41,000
Charge-Offs	0	0	0
Payments	(7,000)	(17,000)	(17,000)
Transfers to ORE	0	0	0
Net Additions/Deletions	0	0	0
Ending Balance	0	7,000	24,000
Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Beginning Balance	1,415,000	1,402,000	1,346,000
Charge-Offs	0	(18,000)	(30,000)
Payments	(881,000)	(272,000)	(323,000)
Transfers to ORE	0	0	(82,000)
Net Additions/Deletions	612,000	303,000	491,000
Ending Balance	1,146,000	1,415,000	1,402,000
Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Beginning Balance	724,000	578,000	539,000
Charge-Offs	0	0	0
Payments	(68,000)	(162,000)	(41,000)
Transfers to ORE	0	0	0
Net Additions/Deletions	150,000	308,000	80,000
Ending Balance	$ 806,000	$ 724,000	$ 578,000