Note 3 - Loans and Allowance for Loan Losses - Loans Modified as Troubled Debt Restructurings (Details)	3 Months Ended
	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)
Originated Loan [Member]
Number of Contracts	4	1
Pre- Modification Recorded Principal Balance	$ 328,000	$ 20,000
Post- Modification Recorded Principal Balance	$ 329,000	$ 20,000
Acquired Loan [Member]
Number of Contracts	4	2
Pre- Modification Recorded Principal Balance	$ 94,000	$ 45,000
Post- Modification Recorded Principal Balance	$ 95,000	$ 45,000
Commercial Portfolio Segment [Member] | Originated Loan [Member]
Number of Contracts	0	1
Pre- Modification Recorded Principal Balance	$ 0	$ 20,000
Post- Modification Recorded Principal Balance	$ 0	$ 20,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Commercial and Industrial [Member]
Number of Contracts	0	1
Pre- Modification Recorded Principal Balance	$ 0	$ 20,000
Post- Modification Recorded Principal Balance	$ 0	$ 20,000
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	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 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	0
Pre- Modification Recorded Principal Balance	$ 31,000	$ 0
Post- Modification Recorded Principal Balance	$ 31,000	$ 0
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Commercial and Industrial [Member]
Number of Contracts	1	0
Pre- Modification Recorded Principal Balance	$ 31,000	$ 0
Post- Modification Recorded Principal Balance	$ 31,000	$ 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	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 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	0
Pre- Modification Recorded Principal Balance	$ 328,000	$ 0
Post- Modification Recorded Principal Balance	$ 329,000	$ 0
Retail Portfolio Segment [Member] | Originated Loan [Member] | Home Equity and Other [Member]
Number of Contracts	4	0
Pre- Modification Recorded Principal Balance	$ 328,000	$ 0
Post- Modification Recorded Principal Balance	$ 329,000	$ 0
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	3	2
Pre- Modification Recorded Principal Balance	$ 63,000	$ 45,000
Post- Modification Recorded Principal Balance	$ 64,000	$ 45,000
Retail Portfolio Segment [Member] | Acquired Loan [Member] | Home Equity and Other [Member]
Number of Contracts	2	1
Pre- Modification Recorded Principal Balance	$ 6,000	$ 26,000
Post- Modification Recorded Principal Balance	$ 7,000	$ 26,000
Retail Portfolio Segment [Member] | Acquired Loan [Member] | One to Four Family Mortgages [Member]
Number of Contracts	1	1
Pre- Modification Recorded Principal Balance	$ 57,000	$ 19,000
Post- Modification Recorded Principal Balance	$ 57,000	$ 19,000