Note 3 - Loans and Allowance for Loan Losses - Loans Modified as Troubled Debt Restructurings (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)
Originated Loan [Member]
Pre- Modification Recorded Principal Balance	$ 3,830,000	$ 384,000	$ 4,159,000	$ 404,000
Post- Modification Recorded Principal Balance	$ 4,010,000	$ 391,000	$ 4,339,000	$ 411,000
Number of Contracts	11	4	15	5
Acquired Loan [Member]
Pre- Modification Recorded Principal Balance	$ 1,073,000	$ 92,000	$ 1,136,000	$ 137,000
Post- Modification Recorded Principal Balance	$ 1,073,000	$ 92,000	$ 1,137,000	$ 137,000
Number of Contracts	7	3	10	5
Commercial Portfolio Segment [Member] | Originated Loan [Member]
Pre- Modification Recorded Principal Balance	$ 3,570,000	$ 167,000	$ 3,570,000	$ 187,000
Post- Modification Recorded Principal Balance	$ 3,749,000	$ 167,000	$ 3,749,000	$ 187,000
Number of Contracts	9	1	9	2
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Commercial and Industrial [Member]
Pre- Modification Recorded Principal Balance	$ 2,752,000	$ 0	$ 2,752,000	$ 20,000
Post- Modification Recorded Principal Balance	$ 2,931,000	$ 0	$ 2,931,000	$ 20,000
Number of Contracts	6	0	6	1
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Pre- Modification Recorded Principal Balance	$ 0	$ 0	$ 0	$ 0
Post- Modification Recorded Principal Balance	$ 0	$ 0	$ 0	$ 0
Number of Contracts	0	0	0	0
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Owner Occupied Loan [Member]
Pre- Modification Recorded Principal Balance	$ 818,000	$ 167,000	$ 818,000	$ 167,000
Post- Modification Recorded Principal Balance	$ 818,000	$ 167,000	$ 818,000	$ 167,000
Number of Contracts	3	1	3	1
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Non Owner Occupied Loan [Member]
Pre- Modification Recorded Principal Balance	$ 0	$ 0	$ 0	$ 0
Post- Modification Recorded Principal Balance	$ 0	$ 0	$ 0	$ 0
Number of Contracts	0	0	0	0
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Pre- Modification Recorded Principal Balance	$ 0	$ 0	$ 0	$ 0
Post- Modification Recorded Principal Balance	$ 0	$ 0	$ 0	$ 0
Number of Contracts	0	0	0	0
Commercial Portfolio Segment [Member] | Acquired Loan [Member]
Pre- Modification Recorded Principal Balance	$ 836,000	$ 67,000	$ 836,000	$ 67,000
Post- Modification Recorded Principal Balance	$ 835,000	$ 67,000	$ 835,000	$ 67,000
Number of Contracts	3	2	3	2
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Commercial and Industrial [Member]
Pre- Modification Recorded Principal Balance	$ 118,000	$ 0	$ 118,000	$ 0
Post- Modification Recorded Principal Balance	$ 117,000	$ 0	$ 117,000	$ 0
Number of Contracts	1	0	1	0
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Pre- Modification Recorded Principal Balance	$ 38,000	$ 0	$ 38,000	$ 0
Post- Modification Recorded Principal Balance	$ 38,000	$ 0	$ 38,000	$ 0
Number of Contracts	1	0	1	0
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Owner Occupied Loan [Member]
Pre- Modification Recorded Principal Balance	$ 0	$ 0	$ 0	$ 0
Post- Modification Recorded Principal Balance	$ 0	$ 0	$ 0	$ 0
Number of Contracts	0	0	0	0
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Non Owner Occupied Loan [Member]
Pre- Modification Recorded Principal Balance	$ 680,000	$ 60,000	$ 680,000	$ 60,000
Post- Modification Recorded Principal Balance	$ 680,000	$ 60,000	$ 680,000	$ 60,000
Number of Contracts	1	1	1	1
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Pre- Modification Recorded Principal Balance	$ 0	$ 7,000	$ 0	$ 7,000
Post- Modification Recorded Principal Balance	$ 0	$ 7,000	$ 0	$ 7,000
Number of Contracts	0	1	0	1
Retail Portfolio Segment [Member] | Originated Loan [Member]
Pre- Modification Recorded Principal Balance	$ 260,000	$ 217,000	$ 589,000	$ 217,000
Post- Modification Recorded Principal Balance	$ 261,000	$ 224,000	$ 590,000	$ 224,000
Number of Contracts	2	3	6	3
Retail Portfolio Segment [Member] | Originated Loan [Member] | Home Equity and Other [Member]
Pre- Modification Recorded Principal Balance	$ 260,000	$ 184,000	$ 589,000	$ 184,000
Post- Modification Recorded Principal Balance	$ 261,000	$ 184,000	$ 590,000	$ 184,000
Number of Contracts	2	2	6	2
Retail Portfolio Segment [Member] | Originated Loan [Member] | One to Four Family Mortgages [Member]
Pre- Modification Recorded Principal Balance	$ 0	$ 33,000	$ 0	$ 33,000
Post- Modification Recorded Principal Balance	$ 0	$ 40,000	$ 0	$ 40,000
Number of Contracts	0	1	0	1
Retail Portfolio Segment [Member] | Acquired Loan [Member]
Pre- Modification Recorded Principal Balance	$ 237,000	$ 25,000	$ 300,000	$ 70,000
Post- Modification Recorded Principal Balance	$ 238,000	$ 25,000	$ 302,000	$ 70,000
Number of Contracts	4	1	7	3
Retail Portfolio Segment [Member] | Acquired Loan [Member] | Home Equity and Other [Member]
Pre- Modification Recorded Principal Balance	$ 160,000	$ 25,000	$ 166,000	$ 51,000
Post- Modification Recorded Principal Balance	$ 161,000	$ 25,000	$ 168,000	$ 51,000
Number of Contracts	3	1	5	2
Retail Portfolio Segment [Member] | Acquired Loan [Member] | One to Four Family Mortgages [Member]
Pre- Modification Recorded Principal Balance	$ 77,000	$ 0	$ 134,000	$ 19,000
Post- Modification Recorded Principal Balance	$ 77,000	$ 0	$ 134,000	$ 19,000
Number of Contracts	1	0	2	1