Note 3 - Loans and Allowance for Loan Losses - Components of Loan Portfolio (Details) - USD ($)	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Period increase (decrease)	6.20%
Loans	$ 2,527,281,000	$ 2,378,620,000
Percent of portfolio	100.00%	100.00%
Commercial Portfolio Segment [Member]
Period increase (decrease)	6.50%
Loans	$ 2,198,593,000	$ 2,065,347,000
Percent of portfolio	87.00%	86.80%
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Period increase (decrease)	9.40%
Loans	$ 780,816,000	$ 713,903,000
Percent of portfolio	30.90%	30.00%
Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Period increase (decrease)	(16.70%)
Loans	$ 29,027,000	$ 34,828,000
Percent of portfolio	1.10%	1.50%
Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Period increase (decrease)	9.10%
Loans	$ 491,633,000	$ 450,464,000
Percent of portfolio	19.50%	18.90%
Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Period increase (decrease)	4.60%
Loans	$ 783,036,000	$ 748,269,000
Percent of portfolio	31.00%	31.50%
Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Period increase (decrease)	(3.20%)
Loans	$ 114,081,000	$ 117,883,000
Percent of portfolio	4.50%	4.90%
Retail Portfolio Segment [Member]
Period increase (decrease)	4.90%
Loans	$ 328,688,000	$ 313,273,000
Percent of portfolio	13.00%	13.20%
Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Period increase (decrease)	(8.50%)
Loans	$ 107,991,000	$ 118,047,000
Percent of portfolio	4.30%	5.00%
Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Period increase (decrease)	13.00%
Loans	$ 220,697,000	$ 195,226,000
Percent of portfolio	8.70%	8.20%
Originated Loan [Member]
Period increase (decrease)	10.30%
Loans	$ 2,078,875,000	$ 1,884,548,000
Percent of portfolio	100.00%	100.00%
Originated Loan [Member] | Commercial Portfolio Segment [Member]
Period increase (decrease)	9.20%
Loans	$ 1,888,130,000	$ 1,728,898,000
Percent of portfolio	90.80%	91.70%
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Period increase (decrease)	11.20%
Loans	$ 708,245,000	$ 636,771,000
Percent of portfolio	34.10%	33.80%
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Period increase (decrease)	(18.30%)
Loans	$ 21,654,000	$ 26,519,000
Percent of portfolio	1.00%	1.40%
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Period increase (decrease)	3.20%
Loans	$ 411,547,000	$ 363,509,000
Percent of portfolio	19.80%	19.30%
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Period increase (decrease)	6.80%
Loans	$ 696,499,000	$ 652,054,000
Percent of portfolio	33.50%	34.60%
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Period increase (decrease)	0.30%
Loans	$ 50,185,000	$ 50,045,000
Percent of portfolio	2.40%	2.60%
Originated Loan [Member] | Retail Portfolio Segment [Member]
Period increase (decrease)	22.50%
Loans	$ 190,745,000	$ 155,650,000
Percent of portfolio	9.20%	8.30%
Originated Loan [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Period increase (decrease)	(0.10%)
Loans	$ 69,788,000	$ 69,831,000
Percent of portfolio	3.40%	3.70%
Originated Loan [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Period increase (decrease)	40.90%
Loans	$ 120,957,000	$ 85,819,000
Percent of portfolio	5.80%	4.60%
Acquired Loan [Member]
Period increase (decrease)	(9.20%)
Loans	$ 448,406,000	$ 494,072,000
Percent of portfolio	100.00%	100.00%
Acquired Loan [Member] | Commercial Portfolio Segment [Member]
Period increase (decrease)	(7.70%)
Loans	$ 310,463,000	$ 336,449,000
Percent of portfolio	69.20%	68.10%
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Period increase (decrease)	(5.90%)
Loans	$ 72,571,000	$ 77,132,000
Percent of portfolio	16.20%	15.60%
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Period increase (decrease)	(11.30%)
Loans	$ 7,373,000	$ 8,309,000
Percent of portfolio	1.60%	1.70%
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Period increase (decrease)	(7.90%)
Loans	$ 80,086,000	$ 86,955,000
Percent of portfolio	17.90%	17.60%
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Period increase (decrease)	(10.10%)
Loans	$ 86,537,000	$ 96,215,000
Percent of portfolio	19.30%	19.50%
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Period increase (decrease)	(5.80%)
Loans	$ 63,896,000	$ 67,838,000
Percent of portfolio	14.20%	13.70%
Acquired Loan [Member] | Retail Portfolio Segment [Member]
Period increase (decrease)	(12.50%)
Loans	$ 137,943,000	$ 157,623,000
Percent of portfolio	30.80%	31.90%
Acquired Loan [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Period increase (decrease)	(20.80%)
Loans	$ 38,203,000	$ 48,216,000
Percent of portfolio	8.50%	9.80%
Acquired Loan [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Period increase (decrease)	(8.80%)
Loans	$ 99,740,000	$ 109,407,000
Percent of portfolio	22.30%	22.10%