Note 3 - Loans and Allowance for Loan Losses - Loans Modified as Troubled Debt Restructurings (Details)	3 Months Ended
	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)
Originated Loan [Member]
Number of Contracts	12	8
Pre- Modification Recorded Principal Balance	$ 661,000	$ 4,022,000
Post- Modification Recorded Principal Balance	$ 3,234,000	$ 4,000,000
Acquired Loan [Member]
Number of Contracts	6	9
Pre- Modification Recorded Principal Balance	$ 792,000	$ 1,715,000
Post- Modification Recorded Principal Balance	$ 781,000	$ 1,716,000
Commercial Portfolio Segment [Member] | Originated Loan [Member]
Number of Contracts	12	7
Pre- Modification Recorded Principal Balance	$ 661,000	$ 3,972,000
Post- Modification Recorded Principal Balance	$ 3,234,000	$ 3,950,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Commercial and Industrial [Member]
Number of Contracts	11	3
Pre- Modification Recorded Principal Balance	$ 591,000	$ 107,000
Post- Modification Recorded Principal Balance	$ 3,164,000	$ 96,000
Commercial Portfolio Segment [Member] | Originated 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] | Originated Loan [Member] | Real Estate Owner Occupied Loan [Member]
Number of Contracts	1	4
Pre- Modification Recorded Principal Balance	$ 70,000	$ 3,865,000
Post- Modification Recorded Principal Balance	$ 70,000	$ 3,854,000
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	3
Pre- Modification Recorded Principal Balance	$ 690,000	$ 1,597,000
Post- Modification Recorded Principal Balance	$ 679,000	$ 1,597,000
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	3
Pre- Modification Recorded Principal Balance	$ 690,000	$ 1,597,000
Post- Modification Recorded Principal Balance	$ 679,000	$ 1,597,000
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	0	1
Pre- Modification Recorded Principal Balance	$ 0	$ 50,000
Post- Modification Recorded Principal Balance	$ 0	$ 50,000
Retail Portfolio Segment [Member] | Originated Loan [Member] | Home Equity and Other [Member]
Number of Contracts	0	1
Pre- Modification Recorded Principal Balance	$ 0	$ 50,000
Post- Modification Recorded Principal Balance	$ 0	$ 50,000
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	5	6
Pre- Modification Recorded Principal Balance	$ 102,000	$ 118,000
Post- Modification Recorded Principal Balance	$ 102,000	$ 119,000
Retail Portfolio Segment [Member] | Acquired Loan [Member] | Home Equity and Other [Member]
Number of Contracts	4	6
Pre- Modification Recorded Principal Balance	$ 70,000	$ 118,000
Post- Modification Recorded Principal Balance	$ 70,000	$ 119,000
Retail Portfolio Segment [Member] | Acquired Loan [Member] | One to Four Family Mortgages [Member]
Number of Contracts	1	0
Pre- Modification Recorded Principal Balance	$ 32,000	$ 0
Post- Modification Recorded Principal Balance	$ 32,000	$ 0