Note 3 - Loans and Allowance for Loan Losses - Loans Modified as Troubled Debt Restructurings (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)
Originated Loan [Member]
Number of Contracts	2	11	7	15
Pre- Modification Recorded Principal Balance	$ 974,000	$ 3,830,000	$ 2,310,000	$ 4,159,000
Post- Modification Recorded Principal Balance	$ 1,079,000	$ 4,010,000	$ 2,392,000	$ 4,339,000
Acquired Loan [Member]
Number of Contracts	6	7	11	10
Pre- Modification Recorded Principal Balance	$ 137,000	$ 1,073,000	$ 241,000	$ 1,136,000
Post- Modification Recorded Principal Balance	$ 138,000	$ 1,073,000	$ 242,000	$ 1,137,000
Commercial Portfolio Segment [Member] | Originated Loan [Member]
Number of Contracts	2	9	6	9
Pre- Modification Recorded Principal Balance	$ 974,000	$ 3,570,000	$ 2,260,000	$ 3,570,000
Post- Modification Recorded Principal Balance	$ 1,079,000	$ 3,749,000	$ 2,342,000	$ 3,749,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Commercial and Industrial [Member]
Number of Contracts	2	6	4	6
Pre- Modification Recorded Principal Balance	$ 974,000	$ 2,752,000	$ 1,068,000	$ 2,752,000
Post- Modification Recorded Principal Balance	$ 1,079,000	$ 2,931,000	$ 1,162,000	$ 2,931,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Number of Contracts	0	0	0	0
Pre- Modification Recorded Principal Balance	$ 0	$ 0	$ 0	$ 0
Post- Modification Recorded Principal Balance	$ 0	$ 0	$ 0	$ 0
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Owner Occupied Loan [Member]
Number of Contracts	0	3	2	3
Pre- Modification Recorded Principal Balance	$ 0	$ 818,000	$ 1,192,000	$ 818,000
Post- Modification Recorded Principal Balance	$ 0	$ 818,000	$ 1,180,000	$ 818,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Non Owner Occupied Loan [Member]
Number of Contracts	0	0	0	0
Pre- Modification Recorded Principal Balance	$ 0	$ 0	$ 0	$ 0
Post- Modification Recorded Principal Balance	$ 0	$ 0	$ 0	$ 0
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Number of Contracts	0	0	0	0
Pre- Modification Recorded Principal Balance	$ 0	$ 0	$ 0	$ 0
Post- Modification Recorded Principal Balance	$ 0	$ 0	$ 0	$ 0
Commercial Portfolio Segment [Member] | Acquired Loan [Member]
Number of Contracts	0	3	0	3
Pre- Modification Recorded Principal Balance	$ 0	$ 836,000	$ 0	$ 836,000
Post- Modification Recorded Principal Balance	$ 0	$ 835,000	$ 0	$ 835,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Commercial and Industrial [Member]
Number of Contracts	0	1	0	1
Pre- Modification Recorded Principal Balance	$ 0	$ 118,000	$ 0	$ 118,000
Post- Modification Recorded Principal Balance	$ 0	$ 117,000	$ 0	$ 117,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Number of Contracts	0	1	0	1
Pre- Modification Recorded Principal Balance	$ 0	$ 38,000	$ 0	$ 38,000
Post- Modification Recorded Principal Balance	$ 0	$ 38,000	$ 0	$ 38,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Owner Occupied Loan [Member]
Number of Contracts	0	0	0	0
Pre- Modification Recorded Principal Balance	$ 0	$ 0	$ 0	$ 0
Post- Modification Recorded Principal Balance	$ 0	$ 0	$ 0	$ 0
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Non Owner Occupied Loan [Member]
Number of Contracts	0	1	0	1
Pre- Modification Recorded Principal Balance	$ 0	$ 680,000	$ 0	$ 680,000
Post- Modification Recorded Principal Balance	$ 0	$ 680,000	$ 0	$ 680,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Number of Contracts	0	0	0	0
Pre- Modification Recorded Principal Balance	$ 0	$ 0	$ 0	$ 0
Post- Modification Recorded Principal Balance	$ 0	$ 0	$ 0	$ 0
Retail Portfolio Segment [Member] | Originated Loan [Member]
Number of Contracts	0	2	1	6
Pre- Modification Recorded Principal Balance	$ 0	$ 260,000	$ 50,000	$ 589,000
Post- Modification Recorded Principal Balance	$ 0	$ 261,000	$ 50,000	$ 590,000
Retail Portfolio Segment [Member] | Originated Loan [Member] | Home Equity and Other [Member]
Number of Contracts	0	2	1	6
Pre- Modification Recorded Principal Balance	$ 0	$ 260,000	$ 50,000	$ 589,000
Post- Modification Recorded Principal Balance	$ 0	$ 261,000	$ 50,000	$ 590,000
Retail Portfolio Segment [Member] | Originated Loan [Member] | One to Four Family Mortgages [Member]
Number of Contracts	0	0	0	0
Pre- Modification Recorded Principal Balance	$ 0	$ 0	$ 0	$ 0
Post- Modification Recorded Principal Balance	$ 0	$ 0	$ 0	$ 0
Retail Portfolio Segment [Member] | Acquired Loan [Member]
Number of Contracts	6	4	11	7
Pre- Modification Recorded Principal Balance	$ 137,000	$ 237,000	$ 241,000	$ 300,000
Post- Modification Recorded Principal Balance	$ 138,000	$ 238,000	$ 242,000	$ 302,000
Retail Portfolio Segment [Member] | Acquired Loan [Member] | Home Equity and Other [Member]
Number of Contracts	5	3	10	5
Pre- Modification Recorded Principal Balance	$ 113,000	$ 160,000	$ 217,000	$ 166,000
Post- Modification Recorded Principal Balance	$ 114,000	$ 161,000	$ 218,000	$ 168,000
Retail Portfolio Segment [Member] | Acquired Loan [Member] | One to Four Family Mortgages [Member]
Number of Contracts	1	1	1	2
Pre- Modification Recorded Principal Balance	$ 24,000	$ 77,000	$ 24,000	$ 134,000
Post- Modification Recorded Principal Balance	$ 24,000	$ 77,000	$ 24,000	$ 134,000