Note 4 - Loans and Allowance for Loan Losses - Loans Modified as Troubled Debt Restructurings (Details)	12 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Originated Loan [Member]
Number of Contracts	12	20
Pre- Modification Recorded Principal Balance	$ 14,644,000	$ 5,636,000
Post- Modification Recorded Principal Balance	$ 14,610,000	$ 5,697,000
Acquired Loan [Member]
Number of Contracts	21	14
Pre- Modification Recorded Principal Balance	$ 655,000	$ 824,000
Post- Modification Recorded Principal Balance	$ 656,000	$ 827,000
Commercial Portfolio Segment [Member] | Originated Loan [Member]
Number of Contracts	10	12
Pre- Modification Recorded Principal Balance	$ 14,581,000	$ 4,966,000
Post- Modification Recorded Principal Balance	$ 14,547,000	$ 5,026,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Commercial and Industrial [Member]
Number of Contracts	9	8
Pre- Modification Recorded Principal Balance	$ 12,297,000	$ 3,771,000
Post- Modification Recorded Principal Balance	$ 12,263,000	$ 3,831,000
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	$ 2,284,000	$ 1,195,000
Post- Modification Recorded Principal Balance	$ 2,284,000	$ 1,195,000
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	$ 150,000	$ 432,000
Post- Modification Recorded Principal Balance	$ 150,000	$ 432,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Commercial and Industrial [Member]
Number of Contracts	0	2
Pre- Modification Recorded Principal Balance	$ 0	$ 399,000
Post- Modification Recorded Principal Balance	$ 0	$ 399,000
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	$ 150,000	$ 33,000
Post- Modification Recorded Principal Balance	$ 150,000	$ 33,000
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	2	8
Pre- Modification Recorded Principal Balance	$ 63,000	$ 670,000
Post- Modification Recorded Principal Balance	$ 63,000	$ 671,000
Retail Portfolio Segment [Member] | Originated Loan [Member] | Home Equity and Other [Member]
Number of Contracts	2	8
Pre- Modification Recorded Principal Balance	$ 63,000	$ 670,000
Post- Modification Recorded Principal Balance	$ 63,000	$ 671,000
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	20	11
Pre- Modification Recorded Principal Balance	$ 505,000	$ 392,000
Post- Modification Recorded Principal Balance	$ 506,000	$ 395,000
Retail Portfolio Segment [Member] | Acquired Loan [Member] | Home Equity and Other [Member]
Number of Contracts	16	7
Pre- Modification Recorded Principal Balance	$ 414,000	$ 192,000
Post- Modification Recorded Principal Balance	$ 416,000	$ 195,000
Retail Portfolio Segment [Member] | Acquired Loan [Member] | One to Four Family Mortgages [Member]
Number of Contracts	4	4
Pre- Modification Recorded Principal Balance	$ 91,000	$ 200,000
Post- Modification Recorded Principal Balance	$ 90,000	$ 200,000