Note 4 - Loans and Allowance for Loan Losses - Activity for Troubled Debt Restructurings (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Commercial and Industrial [Member]
Beginning Balance	$ 13,590,000	$ 2,989,000	$ 1,503,000
Charge-Offs	0	(230,000)	0
Payments	(20,244,000)	(692,000)	(2,021,000)
Transfers to ORE	0	0	0
Net Additions/Deletions	14,812,000	11,523,000	3,507,000
Ending Balance	8,158,000	13,590,000	2,989,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Beginning Balance	0	383,000	1,488,000
Charge-Offs	0	0	0
Payments	(2,000)	(383,000)	(1,105,000)
Transfers to ORE	0	0	0
Net Additions/Deletions	87,000	0	0
Ending Balance	85,000	0	383,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Owner Occupied Loan [Member]
Beginning Balance	2,682,000	1,599,000	906,000
Charge-Offs	0	0	0
Payments	(2,947,000)	(4,999,000)	(242,000)
Transfers to ORE	0	0	0
Net Additions/Deletions	1,250,000	6,082,000	935,000
Ending Balance	985,000	2,682,000	1,599,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Non Owner Occupied Loan [Member]
Beginning Balance	0	0	5,110,000
Charge-Offs	0	0	0
Payments	0	0	(232,000)
Transfers to ORE	0	0	0
Net Additions/Deletions	0	0	(4,878,000)
Ending Balance	0	0	0
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Beginning Balance	0	0	716,000
Charge-Offs	0	0	0
Payments	0	0	(405,000)
Transfers to ORE	0	0	0
Net Additions/Deletions	0	0	(311,000)
Ending Balance	0	0	0
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Commercial and Industrial [Member]
Beginning Balance	548,000	1,001,000	1,125,000
Charge-Offs	0	(275,000)	0
Payments	(120,000)	(100,000)	(550,000)
Transfers to ORE	0	0	0
Net Additions/Deletions	1,000	(78,000)	426,000
Ending Balance	429,000	548,000	1,001,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Beginning Balance	0	0	0
Charge-Offs	0	0	0
Payments	0	0	(33,000)
Transfers to ORE	0	0	0
Net Additions/Deletions	0	0	33,000
Ending Balance	0	0	0
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Owner Occupied Loan [Member]
Beginning Balance	418,000	427,000	900,000
Charge-Offs	0	0	(249,000)
Payments	(873,000)	(1,664,000)	(257,000)
Transfers to ORE	(97,000)	(93,000)	0
Net Additions/Deletions	712,000	1,748,000	33,000
Ending Balance	160,000	418,000	427,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Non Owner Occupied Loan [Member]
Beginning Balance	210,000	237,000	728,000
Charge-Offs	0	0	0
Payments	(32,000)	(27,000)	(922,000)
Transfers to ORE	0	0	(291,000)
Net Additions/Deletions	0	0	722,000
Ending Balance	178,000	210,000	237,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Beginning Balance	24,000	41,000	60,000
Charge-Offs	0	0	0
Payments	(17,000)	(17,000)	(1,084,000)
Transfers to ORE	0	0	0
Net Additions/Deletions	0	0	1,065,000
Ending Balance	7,000	24,000	41,000
Retail Portfolio Segment [Member] | Originated Loan [Member] | Home Equity and Other [Member]
Beginning Balance	938,000	1,127,000	385,000
Charge-Offs	0	0	0
Payments	(114,000)	(251,000)	(57,000)
Transfers to ORE	0	0	0
Net Additions/Deletions	50,000	62,000	799,000
Ending Balance	874,000	938,000	1,127,000
Retail Portfolio Segment [Member] | Originated Loan [Member] | One to Four Family Mortgages [Member]
Beginning Balance	142,000	146,000	157,000
Charge-Offs	0	0	0
Payments	(110,000)	(4,000)	(11,000)
Transfers to ORE	0	0	0
Net Additions/Deletions	0	0	0
Ending Balance	32,000	142,000	146,000
Retail Portfolio Segment [Member] | Acquired Loan [Member] | Home Equity and Other [Member]
Beginning Balance	464,000	219,000	208,000
Charge-Offs	(18,000)	(30,000)	(25,000)
Payments	(158,000)	(72,000)	(121,000)
Transfers to ORE	0	(82,000)	0
Net Additions/Deletions	253,000	429,000	157,000
Ending Balance	541,000	464,000	219,000
Retail Portfolio Segment [Member] | Acquired Loan [Member] | One to Four Family Mortgages [Member]
Beginning Balance	436,000	393,000	326,000
Charge-Offs	0	0	0
Payments	(52,000)	(37,000)	(188,000)
Transfers to ORE	0	0	0
Net Additions/Deletions	308,000	80,000	255,000
Ending Balance	$ 692,000	$ 436,000	$ 393,000