Note 3 - Loans and Allowance for Loan Losses - Components of Loan Portfolio (Details) - USD ($)	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Loans	$ 2,881,493,000	$ 2,753,085,000
Percent of portfolio	100.00%	100.00%
Period increase (decrease)	4.70%
Commercial Portfolio Segment [Member]
Loans	$ 2,464,555,000	$ 2,360,106,000
Percent of portfolio	85.50%	85.70%
Period increase (decrease)	4.40%
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans	$ 881,196,000	$ 822,723,000
Percent of portfolio	30.60%	29.90%
Period increase (decrease)	7.10%
Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Loans	$ 45,158,000	$ 44,885,000
Percent of portfolio	1.60%	1.60%
Period increase (decrease)	0.60%
Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Loans	$ 556,868,000	$ 548,619,000
Percent of portfolio	19.30%	19.90%
Period increase (decrease)	1.50%
Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Loans	$ 852,844,000	$ 816,282,000
Percent of portfolio	29.60%	29.70%
Period increase (decrease)	4.50%
Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Loans	$ 128,489,000	$ 127,597,000
Percent of portfolio	4.40%	4.60%
Period increase (decrease)	0.70%
Retail Portfolio Segment [Member]
Loans	$ 416,938,000	$ 392,979,000
Percent of portfolio	14.50%	14.30%
Period increase (decrease)	6.10%
Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Loans	$ 81,320,000	$ 85,439,000
Percent of portfolio	2.80%	3.10%
Period increase (decrease)	(4.80%)
Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Loans	$ 335,618,000	$ 307,540,000
Percent of portfolio	11.70%	11.20%
Period increase (decrease)	9.10%
Originated Loan [Member]
Loans	$ 2,609,686,000	$ 2,452,446,000
Percent of portfolio	100.00%	100.00%
Period increase (decrease)	6.40%
Originated Loan [Member] | Commercial Portfolio Segment [Member]
Loans	$ 2,274,931,000	$ 2,151,998,000
Percent of portfolio	87.20%	87.70%
Period increase (decrease)	5.70%
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans	$ 833,589,000	$ 768,698,000
Percent of portfolio	31.90%	31.30%
Period increase (decrease)	8.40%
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Loans	$ 40,609,000	$ 39,950,000
Percent of portfolio	1.60%	1.60%
Period increase (decrease)	1.60%
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Loans	$ 513,016,000	$ 500,188,000
Percent of portfolio	19.70%	20.40%
Period increase (decrease)	2.60%
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Loans	$ 786,666,000	$ 745,127,000
Percent of portfolio	30.10%	30.40%
Period increase (decrease)	5.60%
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Loans	$ 101,051,000	$ 98,035,000
Percent of portfolio	3.90%	4.00%
Period increase (decrease)	3.10%
Originated Loan [Member] | Retail Portfolio Segment [Member]
Loans	$ 334,755,000	$ 300,448,000
Percent of portfolio	12.80%	12.30%
Period increase (decrease)	11.40%
Originated Loan [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Loans	$ 64,247,000	$ 65,023,000
Percent of portfolio	2.40%	2.70%
Period increase (decrease)	(1.20%)
Originated Loan [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Loans	$ 270,508,000	$ 235,425,000
Percent of portfolio	10.40%	9.60%
Period increase (decrease)	14.90%
Acquired Loan [Member]
Loans	$ 271,807,000	$ 300,639,000
Percent of portfolio	100.00%	100.00%
Period increase (decrease)	(9.60%)
Acquired Loan [Member] | Commercial Portfolio Segment [Member]
Loans	$ 189,624,000	$ 208,108,000
Percent of portfolio	69.80%	69.20%
Period increase (decrease)	(8.90%)
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans	$ 47,607,000	$ 54,025,000
Percent of portfolio	17.50%	18.00%
Period increase (decrease)	(11.90%)
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Loans	$ 4,549,000	$ 4,935,000
Percent of portfolio	1.70%	1.60%
Period increase (decrease)	(7.80%)
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Loans	$ 43,852,000	$ 48,431,000
Percent of portfolio	16.20%	16.10%
Period increase (decrease)	(9.50%)
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Loans	$ 66,178,000	$ 71,155,000
Percent of portfolio	24.30%	23.70%
Period increase (decrease)	(7.00%)
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Loans	$ 27,438,000	$ 29,562,000
Percent of portfolio	10.10%	9.80%
Period increase (decrease)	(7.20%)
Acquired Loan [Member] | Retail Portfolio Segment [Member]
Loans	$ 82,183,000	$ 92,531,000
Percent of portfolio	30.20%	30.80%
Period increase (decrease)	(11.20%)
Acquired Loan [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Loans	$ 17,073,000	$ 20,416,000
Percent of portfolio	6.30%	6.80%
Period increase (decrease)	(16.40%)
Acquired Loan [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Loans	$ 65,110,000	$ 72,115,000
Percent of portfolio	23.90%	24.00%
Period increase (decrease)	(9.70%)