Note 4 - Loans and Allowance for Loan Losses - Components of Loan Portfolio (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Loans	$ 2,856,667,000	$ 2,753,085,000
Percent of portfolio	100.00%	100.00%
Period increase (decrease)	3.80%
Commercial Portfolio Segment [Member]
Loans	$ 2,441,544,000	$ 2,360,106,000
Percent of portfolio	85.50%	85.70%
Period increase (decrease)	3.50%
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans	$ 846,551,000	$ 822,723,000
Percent of portfolio	29.60%	29.90%
Period increase (decrease)	2.90%
Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Loans	$ 56,119,000	$ 44,885,000
Percent of portfolio	2.00%	1.60%
Period increase (decrease)	25.00%
Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Loans	$ 579,003,000	$ 548,619,000
Percent of portfolio	20.30%	19.90%
Period increase (decrease)	5.50%
Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Loans	$ 835,346,000	$ 816,282,000
Percent of portfolio	29.20%	29.70%
Period increase (decrease)	2.30%
Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Loans	$ 124,525,000	$ 127,597,000
Percent of portfolio	4.40%	4.60%
Period increase (decrease)	(2.40%)
Retail Portfolio Segment [Member]
Loans	$ 415,123,000	$ 392,979,000
Percent of portfolio	14.50%	14.30%
Period increase (decrease)	5.60%
Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Loans	$ 75,374,000	$ 85,439,000
Percent of portfolio	2.60%	3.10%
Period increase (decrease)	(11.80%)
Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Loans	$ 339,749,000	$ 307,540,000
Percent of portfolio	11.90%	11.20%
Period increase (decrease)	10.50%
Originated Loan [Member]
Loans	$ 2,614,725,000	$ 2,452,446,000	$ 2,169,957,000
Percent of portfolio	100.00%	100.00%
Period increase (decrease)	6.60%
Originated Loan [Member] | Commercial Portfolio Segment [Member]
Loans	$ 2,271,417,000	$ 2,151,998,000	1,934,228,000
Percent of portfolio	86.90%	87.70%
Period increase (decrease)	5.50%
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans	$ 799,421,000	$ 768,698,000
Percent of portfolio	30.60%	31.30%
Period increase (decrease)	4.00%
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Loans	$ 52,097,000	$ 39,950,000
Percent of portfolio	2.00%	1.60%
Period increase (decrease)	30.40%
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Loans	$ 542,561,000	$ 500,188,000
Percent of portfolio	20.80%	20.40%
Period increase (decrease)	8.50%
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Loans	$ 776,994,000	$ 745,127,000
Percent of portfolio	29.70%	30.40%
Period increase (decrease)	4.30%
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Loans	$ 100,344,000	$ 98,035,000
Percent of portfolio	3.80%	4.00%
Period increase (decrease)	2.40%
Originated Loan [Member] | Retail Portfolio Segment [Member]
Loans	$ 343,308,000	$ 300,448,000	$ 235,729,000
Percent of portfolio	13.10%	12.30%
Period increase (decrease)	14.30%
Originated Loan [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Loans	$ 61,060,000	$ 65,023,000
Percent of portfolio	2.30%	2.70%
Period increase (decrease)	(6.10%)
Originated Loan [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Loans	$ 282,248,000	$ 235,425,000
Percent of portfolio	10.80%	9.60%
Period increase (decrease)	19.90%
Acquired Loan [Member]
Loans	$ 241,942,000	$ 300,639,000
Percent of portfolio	100.00%	100.00%
Period increase (decrease)	(19.50%)
Acquired Loan [Member] | Commercial Portfolio Segment [Member]
Loans	$ 170,127,000	$ 208,108,000
Percent of portfolio	70.30%	69.20%
Period increase (decrease)	(18.30%)
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans	$ 47,130,000	$ 54,025,000
Percent of portfolio	19.40%	18.00%
Period increase (decrease)	(12.80%)
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Loans	$ 4,022,000	$ 4,935,000
Percent of portfolio	1.70%	1.60%
Period increase (decrease)	(18.50%)
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Loans	$ 36,442,000	$ 48,431,000
Percent of portfolio	15.10%	16.10%
Period increase (decrease)	(24.80%)
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Loans	$ 58,352,000	$ 71,155,000
Percent of portfolio	24.10%	23.70%
Period increase (decrease)	(18.00%)
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Loans	$ 24,181,000	$ 29,562,000
Percent of portfolio	10.00%	9.80%
Period increase (decrease)	(18.20%)
Acquired Loan [Member] | Retail Portfolio Segment [Member]
Loans	$ 71,815,000	$ 92,531,000
Percent of portfolio	29.70%	30.80%
Period increase (decrease)	(22.40%)
Acquired Loan [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Loans	$ 14,314,000	$ 20,416,000
Percent of portfolio	5.90%	6.80%
Period increase (decrease)	(29.90%)
Acquired Loan [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Loans	$ 57,501,000	$ 72,115,000
Percent of portfolio	23.80%	24.00%
Period increase (decrease)	(20.30%)