Note 3 - Loans and Allowance for Loan Losses - Components of Loan Portfolio (Details) - USD ($)	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans	$ 667,051,000	$ 577,872,000
Percent of portfolio	35.60%	35.70%
Period increase (decrease)	15.40%
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Loans	$ 28,003,000	$ 30,138,000
Percent of portfolio	1.50%	1.90%
Period increase (decrease)	(7.10%)
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Loans	$ 346,323,000	$ 330,798,000
Percent of portfolio	18.50%	20.50%
Period increase (decrease)	4.70%
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Loans	$ 638,090,000	$ 520,754,000
Percent of portfolio	34.10%	32.20%
Period increase (decrease)	22.50%
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residentia lRental Loan [Member]
Loans	$ 46,239,000	$ 33,954,000
Percent of portfolio	2.40%	2.10%
Period increase (decrease)	36.20%
Originated Loan [Member] | Commercial Portfolio Segment [Member]
Loans	$ 1,725,706,000	$ 1,493,516,000	$ 1,402,320,000
Percent of portfolio	92.10%	92.40%
Period increase (decrease)	15.50%
Originated Loan [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Loans	$ 72,680,000	$ 67,816,000
Percent of portfolio	3.90%	4.20%
Period increase (decrease)	7.20%
Originated Loan [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Loans	$ 74,835,000	$ 55,255,000
Percent of portfolio	4.00%	3.40%
Period increase (decrease)	35.40%
Originated Loan [Member] | Retail Portfolio Segment [Member]
Loans	$ 147,515,000	$ 123,071,000	117,390,000
Percent of portfolio	7.90%	7.60%
Period increase (decrease)	19.90%
Originated Loan [Member]
Loans	$ 1,873,221,000	$ 1,616,587,000	$ 1,519,710,000
Percent of portfolio	100.00%	100.00%
Period increase (decrease)	15.90%
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans	$ 83,279,000	$ 118,431,000
Percent of portfolio	15.60%	17.90%
Period increase (decrease)	(29.70%)
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Loans	$ 9,452,000	$ 14,982,000
Percent of portfolio	1.80%	2.30%
Period increase (decrease)	(36.90%)
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Loans	$ 94,381,000	$ 115,121,000
Percent of portfolio	17.70%	17.40%
Period increase (decrease)	(18.00%)
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Loans	$ 103,354,000	$ 123,597,000
Percent of portfolio	19.40%	18.70%
Period increase (decrease)	(16.40%)
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residentia lRental Loan [Member]
Loans	$ 71,864,000	$ 81,049,000
Percent of portfolio	13.50%	12.30%
Period increase (decrease)	(11.30%)
Acquired Loan [Member] | Commercial Portfolio Segment [Member]
Loans	$ 362,330,000	$ 453,180,000
Percent of portfolio	68.00%	68.60%
Period increase (decrease)	(20.00%)
Acquired Loan [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Loans	$ 54,946,000	$ 72,830,000
Percent of portfolio	10.30%	11.00%
Period increase (decrease)	(24.60%)
Acquired Loan [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Loans	$ 115,880,000	$ 135,130,000
Percent of portfolio	21.70%	20.40%
Period increase (decrease)	(14.20%)
Acquired Loan [Member] | Retail Portfolio Segment [Member]
Loans	$ 170,826,000	$ 207,960,000
Percent of portfolio	32.00%	31.40%
Period increase (decrease)	(17.90%)
Acquired Loan [Member]
Loans	$ 533,156,000	$ 661,140,000
Percent of portfolio	100.00%	100.00%
Period increase (decrease)	(19.40%)
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans	$ 750,330,000	$ 696,303,000
Percent of portfolio	31.20%	30.60%
Period increase (decrease)	7.80%
Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Loans	$ 37,455,000	$ 45,120,000
Percent of portfolio	1.60%	2.00%
Period increase (decrease)	(17.00%)
Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Loans	$ 440,704,000	$ 445,919,000
Percent of portfolio	18.30%	19.60%
Period increase (decrease)	(1.20%)
Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Loans	$ 741,444,000	$ 644,351,000
Percent of portfolio	30.80%	28.30%
Period increase (decrease)	15.10%
Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residentia lRental Loan [Member]
Loans	$ 118,103,000	$ 115,003,000
Percent of portfolio	4.90%	5.00%
Period increase (decrease)	2.70%
Commercial Portfolio Segment [Member]
Loans	$ 2,088,036,000	$ 1,946,696,000
Percent of portfolio	86.80%	85.50%
Period increase (decrease)	7.30%
Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Loans	$ 127,626,000	$ 140,646,000
Percent of portfolio	5.30%	6.20%
Period increase (decrease)	(9.30%)
Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Loans	$ 190,715,000	$ 190,385,000
Percent of portfolio	7.90%	8.30%
Period increase (decrease)	0.20%
Retail Portfolio Segment [Member]
Loans	$ 318,341,000	$ 331,031,000
Percent of portfolio	13.20%	14.50%
Period increase (decrease)	(3.80%)
Loans	$ 2,406,377,000	$ 2,277,727,000
Percent of portfolio	100.00%	100.00%
Period increase (decrease)	5.60%