Note 3 - Loans and Allowance for Loan Losses - Loans Modified as Troubled Debt Restructurings (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)
Originated Loan [Member]
Number of Contracts	6	1	20	6
Pre- Modification Recorded Principal Balance	$ 1,907,000	$ 56,000	$ 5,966,000	$ 460,000
Post- Modification Recorded Principal Balance	$ 1,907,000	$ 56,000	$ 6,146,000	$ 467,000
Acquired Loan [Member]
Number of Contracts	6	2	16	7
Pre- Modification Recorded Principal Balance	$ 1,551,000	$ 47,000	$ 2,687,000	$ 184,000
Post- Modification Recorded Principal Balance	$ 1,551,000	$ 47,000	$ 2,688,000	$ 184,000
Commercial Portfolio Segment [Member] | Originated Loan [Member]
Number of Contracts	5	0	13	2
Pre- Modification Recorded Principal Balance	$ 1,839,000	$ 0	$ 5,309,000	$ 187,000
Post- Modification Recorded Principal Balance	$ 1,839,000	$ 0	$ 5,488,000	$ 187,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Commercial and Industrial [Member]
Number of Contracts	3	0	9	1
Pre- Modification Recorded Principal Balance	$ 1,362,000	$ 0	$ 4,114,000	$ 20,000
Post- Modification Recorded Principal Balance	$ 1,362,000	$ 0	$ 4,293,000	$ 20,000
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	2	0	4	1
Pre- Modification Recorded Principal Balance	$ 477,000	$ 0	$ 1,195,000	$ 167,000
Post- Modification Recorded Principal Balance	$ 477,000	$ 0	$ 1,195,000	$ 167,000
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	3	1	6	3
Pre- Modification Recorded Principal Balance	$ 1,410,000	$ 44,000	$ 2,246,000	$ 111,000
Post- Modification Recorded Principal Balance	$ 1,410,000	$ 44,000	$ 2,245,000	$ 111,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Commercial and Industrial [Member]
Number of Contracts	1	0	2	0
Pre- Modification Recorded Principal Balance	$ 282,000	$ 0	$ 399,000	$ 0
Post- Modification Recorded Principal Balance	$ 282,000	$ 0	$ 399,000	$ 0
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Number of Contracts	0	0	1	0
Pre- Modification Recorded Principal Balance	$ 0	$ 0	$ 38,000	$ 0
Post- Modification Recorded Principal Balance	$ 0	$ 0	$ 38,000	$ 0
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Owner Occupied Loan [Member]
Number of Contracts	0	1	0	1
Pre- Modification Recorded Principal Balance	$ 0	$ 44,000	$ 0	$ 44,000
Post- Modification Recorded Principal Balance	$ 0	$ 44,000	$ 0	$ 44,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Non Owner Occupied Loan [Member]
Number of Contracts	1	0	2	1
Pre- Modification Recorded Principal Balance	$ 64,000	$ 0	$ 745,000	$ 60,000
Post- Modification Recorded Principal Balance	$ 64,000	$ 0	$ 744,000	$ 60,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Number of Contracts	1	0	1	1
Pre- Modification Recorded Principal Balance	$ 1,064,000	$ 0	$ 1,064,000	$ 7,000
Post- Modification Recorded Principal Balance	$ 1,064,000	$ 0	$ 1,064,000	$ 7,000
Retail Portfolio Segment [Member] | Originated Loan [Member]
Number of Contracts	1	1	7	4
Pre- Modification Recorded Principal Balance	$ 68,000	$ 56,000	$ 657,000	$ 273,000
Post- Modification Recorded Principal Balance	$ 68,000	$ 56,000	$ 658,000	$ 280,000
Retail Portfolio Segment [Member] | Originated Loan [Member] | Home Equity and Other [Member]
Number of Contracts	1	1	7	3
Pre- Modification Recorded Principal Balance	$ 68,000	$ 56,000	$ 657,000	$ 240,000
Post- Modification Recorded Principal Balance	$ 68,000	$ 56,000	$ 658,000	$ 240,000
Retail Portfolio Segment [Member] | Originated Loan [Member] | One to Four Family Mortgages [Member]
Number of Contracts	0	0	0	1
Pre- Modification Recorded Principal Balance	$ 0	$ 0	$ 0	$ 33,000
Post- Modification Recorded Principal Balance	$ 0	$ 0	$ 0	$ 40,000
Retail Portfolio Segment [Member] | Acquired Loan [Member]
Number of Contracts	3	1	10	4
Pre- Modification Recorded Principal Balance	$ 141,000	$ 3,000	$ 441,000	$ 73,000
Post- Modification Recorded Principal Balance	$ 141,000	$ 3,000	$ 443,000	$ 73,000
Retail Portfolio Segment [Member] | Acquired Loan [Member] | Home Equity and Other [Member]
Number of Contracts	2	1	7	3
Pre- Modification Recorded Principal Balance	$ 90,000	$ 3,000	$ 256,000	$ 54,000
Post- Modification Recorded Principal Balance	$ 90,000	$ 3,000	$ 258,000	$ 54,000
Retail Portfolio Segment [Member] | Acquired Loan [Member] | One to Four Family Mortgages [Member]
Number of Contracts	1	0	3	1
Pre- Modification Recorded Principal Balance	$ 51,000	$ 0	$ 185,000	$ 19,000
Post- Modification Recorded Principal Balance	$ 51,000	$ 0	$ 185,000	$ 19,000