Note 3 - Loans and Allowance for Loan Losses - Loans Modified as Troubled Debt Restructurings (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)
Originated Loan [Member]
Number of Contracts	3	6	12	12
Pre- Modification Recorded Principal Balance	$ 129,000	$ 5,402,000	$ 16,148,000	$ 7,497,000
Post- Modification Recorded Principal Balance	$ 129,000	$ 5,248,000	$ 16,445,000	$ 7,437,000
Acquired Loan [Member]
Number of Contracts	6	3	16	14
Pre- Modification Recorded Principal Balance	$ 199,000	$ 195,000	$ 492,000	$ 437,000
Post- Modification Recorded Principal Balance	$ 198,000	$ 191,000	$ 493,000	$ 433,000
Commercial Portfolio Segment [Member] | Originated Loan [Member]
Number of Contracts	2	6	9	11
Pre- Modification Recorded Principal Balance	$ 115,000	$ 5,402,000	$ 16,111,000	$ 7,447,000
Post- Modification Recorded Principal Balance	$ 115,000	$ 5,248,000	$ 16,408,000	$ 7,387,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Commercial and Industrial [Member]
Number of Contracts	1	5	7	9
Pre- Modification Recorded Principal Balance	$ 28,000	$ 3,118,000	$ 14,457,000	$ 4,186,000
Post- Modification Recorded Principal Balance	$ 28,000	$ 2,964,000	$ 14,754,000	$ 4,126,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Number of Contracts	1	0	1	0
Pre- Modification Recorded Principal Balance	$ 87,000	$ 0	$ 87,000	$ 0
Post- Modification Recorded Principal Balance	$ 87,000	$ 0	$ 87,000	$ 0
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Owner Occupied Loan [Member]
Number of Contracts	0	1	1	2
Pre- Modification Recorded Principal Balance	$ 0	$ 2,284,000	$ 1,567,000	$ 3,261,000
Post- Modification Recorded Principal Balance	$ 0	$ 2,284,000	$ 1,567,000	$ 3,261,000
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	1	2	1	2
Pre- Modification Recorded Principal Balance	$ 102,000	$ 183,000	$ 102,000	$ 183,000
Post- Modification Recorded Principal Balance	$ 102,000	$ 179,000	$ 102,000	$ 179,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Commercial and Industrial [Member]
Number of Contracts	0	1	0	1
Pre- Modification Recorded Principal Balance	$ 0	$ 33,000	$ 0	$ 33,000
Post- Modification Recorded Principal Balance	$ 0	$ 29,000	$ 0	$ 29,000
Commercial Portfolio Segment [Member] | Acquired 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] | Acquired Loan [Member] | Real Estate Owner Occupied Loan [Member]
Number of Contracts	1	1	1	1
Pre- Modification Recorded Principal Balance	$ 102,000	$ 150,000	$ 102,000	$ 150,000
Post- Modification Recorded Principal Balance	$ 102,000	$ 150,000	$ 102,000	$ 150,000
Commercial Portfolio Segment [Member] | Acquired 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] | 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	1	0	3	1
Pre- Modification Recorded Principal Balance	$ 14,000	$ 0	$ 37,000	$ 50,000
Post- Modification Recorded Principal Balance	$ 14,000	$ 0	$ 37,000	$ 50,000
Retail Portfolio Segment [Member] | Originated Loan [Member] | Home Equity and Other [Member]
Number of Contracts	1	0	3	1
Pre- Modification Recorded Principal Balance	$ 14,000	$ 0	$ 37,000	$ 50,000
Post- Modification Recorded Principal Balance	$ 14,000	$ 0	$ 37,000	$ 50,000
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	5	1	15	12
Pre- Modification Recorded Principal Balance	$ 97,000	$ 12,000	$ 390,000	$ 254,000
Post- Modification Recorded Principal Balance	$ 96,000	$ 12,000	$ 391,000	$ 254,000
Retail Portfolio Segment [Member] | Acquired Loan [Member] | Home Equity and Other [Member]
Number of Contracts	4	0	10	10
Pre- Modification Recorded Principal Balance	$ 48,000	$ 0	$ 188,000	$ 217,000
Post- Modification Recorded Principal Balance	$ 47,000	$ 0	$ 188,000	$ 218,000
Retail Portfolio Segment [Member] | Acquired Loan [Member] | One to Four Family Mortgages [Member]
Number of Contracts	1	1	5	2
Pre- Modification Recorded Principal Balance	$ 49,000	$ 12,000	$ 202,000	$ 37,000
Post- Modification Recorded Principal Balance	$ 49,000	$ 12,000	$ 203,000	$ 36,000