Note 4 - Loans and Allowance for Loan Losses - Loans Modified as Troubled Debt Restructurings (Details)	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Originated Loan [Member]
Number of Contracts	11	12
Pre- Modification Recorded Principal Balance	$ 2,140,000	$ 14,644,000
Post- Modification Recorded Principal Balance	$ 2,140,000	$ 14,610,000
Acquired Loan [Member]
Number of Contracts	25	21
Pre- Modification Recorded Principal Balance	$ 656,000	$ 655,000
Post- Modification Recorded Principal Balance	$ 657,000	$ 656,000
Commercial Portfolio Segment [Member] | Originated Loan [Member]
Number of Contracts	7	10
Pre- Modification Recorded Principal Balance	$ 2,089,000	$ 14,581,000
Post- Modification Recorded Principal Balance	$ 2,089,000	$ 14,547,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Commercial and Industrial [Member]
Number of Contracts	5	9
Pre- Modification Recorded Principal Balance	$ 435,000	$ 12,297,000
Post- Modification Recorded Principal Balance	$ 435,000	$ 12,263,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Number of Contracts	1	0
Pre- Modification Recorded Principal Balance	$ 87,000	$ 0
Post- Modification Recorded Principal Balance	$ 87,000	$ 0
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Owner Occupied Loan [Member]
Number of Contracts	1	1
Pre- Modification Recorded Principal Balance	$ 1,567,000	$ 2,284,000
Post- Modification Recorded Principal Balance	$ 1,567,000	$ 2,284,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Non Owner Occupied Loan [Member]
Number of Contracts	0	0
Pre- Modification Recorded Principal Balance	$ 0	$ 0
Post- Modification Recorded Principal Balance	$ 0	$ 0
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Number of Contracts	0	0
Pre- Modification Recorded Principal Balance	$ 0	$ 0
Post- Modification Recorded Principal Balance	$ 0	$ 0
Commercial Portfolio Segment [Member] | Acquired Loan [Member]
Number of Contracts	1	1
Pre- Modification Recorded Principal Balance	$ 102,000	$ 150,000
Post- Modification Recorded Principal Balance	$ 102,000	$ 150,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Commercial and Industrial [Member]
Number of Contracts	0	0
Pre- Modification Recorded Principal Balance	$ 0	$ 0
Post- Modification Recorded Principal Balance	$ 0	$ 0
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Number of Contracts	0	0
Pre- Modification Recorded Principal Balance	$ 0	$ 0
Post- Modification Recorded Principal Balance	$ 0	$ 0
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Owner Occupied Loan [Member]
Number of Contracts	1	1
Pre- Modification Recorded Principal Balance	$ 102,000	$ 150,000
Post- Modification Recorded Principal Balance	$ 102,000	$ 150,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Non Owner Occupied Loan [Member]
Number of Contracts	0	0
Pre- Modification Recorded Principal Balance	$ 0	$ 0
Post- Modification Recorded Principal Balance	$ 0	$ 0
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Number of Contracts	0	0
Pre- Modification Recorded Principal Balance	$ 0	$ 0
Post- Modification Recorded Principal Balance	$ 0	$ 0
Retail Portfolio Segment [Member] | Originated Loan [Member]
Number of Contracts	4	2
Pre- Modification Recorded Principal Balance	$ 51,000	$ 63,000
Post- Modification Recorded Principal Balance	$ 51,000	$ 63,000
Retail Portfolio Segment [Member] | Originated Loan [Member] | Home Equity and Other [Member]
Number of Contracts	4	2
Pre- Modification Recorded Principal Balance	$ 51,000	$ 63,000
Post- Modification Recorded Principal Balance	$ 51,000	$ 63,000
Retail Portfolio Segment [Member] | Originated Loan [Member] | One to Four Family Mortgages [Member]
Number of Contracts	0	0
Pre- Modification Recorded Principal Balance	$ 0	$ 0
Post- Modification Recorded Principal Balance	$ 0	$ 0
Retail Portfolio Segment [Member] | Acquired Loan [Member]
Number of Contracts	24	20
Pre- Modification Recorded Principal Balance	$ 554,000	$ 505,000
Post- Modification Recorded Principal Balance	$ 555,000	$ 506,000
Retail Portfolio Segment [Member] | Acquired Loan [Member] | Home Equity and Other [Member]
Number of Contracts	16	16
Pre- Modification Recorded Principal Balance	$ 244,000	$ 414,000
Post- Modification Recorded Principal Balance	$ 245,000	$ 416,000
Retail Portfolio Segment [Member] | Acquired Loan [Member] | One to Four Family Mortgages [Member]
Number of Contracts	8	4
Pre- Modification Recorded Principal Balance	$ 310,000	$ 91,000
Post- Modification Recorded Principal Balance	$ 310,000	$ 90,000