Note 3 - Loans and Allowance for Loan Losses - Components of Loan Portfolio (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Loans	$ 2,441,314,000	$ 2,378,620,000
Percent of portfolio	100.00%	100.00%
Period increase (decrease)	2.60%
Commercial Portfolio Segment [Member]
Loans	$ 2,123,348,000	$ 2,065,347,000
Percent of portfolio	87.00%	86.80%
Period increase (decrease)	2.80%
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans	$ 757,220,000	$ 713,903,000
Percent of portfolio	31.00%	30.00%
Period increase (decrease)	6.10%
Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Loans	$ 31,924,000	$ 34,828,000
Percent of portfolio	1.30%	1.50%
Period increase (decrease)	(8.30%)
Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Loans	$ 452,382,000	$ 450,464,000
Percent of portfolio	18.50%	18.90%
Period increase (decrease)	0.40%
Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Loans	$ 768,565,000	$ 748,269,000
Percent of portfolio	31.50%	31.50%
Period increase (decrease)	2.70%
Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Loans	$ 113,257,000	$ 117,883,000
Percent of portfolio	4.70%	4.90%
Period increase (decrease)	(3.90%)
Retail Portfolio Segment [Member]
Loans	$ 317,966,000	$ 313,273,000
Percent of portfolio	13.00%	13.20%
Period increase (decrease)	1.50%
Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Loans	$ 112,117,000	$ 118,047,000
Percent of portfolio	4.60%	5.00%
Period increase (decrease)	(5.00%)
Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Loans	$ 205,849,000	$ 195,226,000
Percent of portfolio	8.40%	8.20%
Period increase (decrease)	5.40%
Originated Loan [Member]
Loans	$ 1,973,739,000	$ 1,884,548,000
Percent of portfolio	100.00%	100.00%
Period increase (decrease)	4.70%
Originated Loan [Member] | Commercial Portfolio Segment [Member]
Loans	$ 1,803,409,000	$ 1,728,898,000
Percent of portfolio	91.40%	91.70%
Period increase (decrease)	4.30%
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans	$ 685,227,000	$ 636,771,000
Percent of portfolio	34.70%	33.80%
Period increase (decrease)	7.60%
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Loans	$ 23,841,000	$ 26,519,000
Percent of portfolio	1.20%	1.40%
Period increase (decrease)	(10.10%)
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Loans	$ 368,910,000	$ 363,509,000
Percent of portfolio	18.70%	19.30%
Period increase (decrease)	1.50%
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Loans	$ 678,359,000	$ 652,054,000
Percent of portfolio	34.40%	34.60%
Period increase (decrease)	4.00%
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Loans	$ 47,072,000	$ 50,045,000
Percent of portfolio	2.40%	2.60%
Period increase (decrease)	(5.90%)
Originated Loan [Member] | Retail Portfolio Segment [Member]
Loans	$ 170,330,000	$ 155,650,000
Percent of portfolio	8.60%	8.30%
Period increase (decrease)	9.40%
Originated Loan [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Loans	$ 69,032,000	$ 69,831,000
Percent of portfolio	3.50%	3.70%
Period increase (decrease)	(1.10%)
Originated Loan [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Loans	$ 101,298,000	$ 85,819,000
Percent of portfolio	5.10%	4.60%
Period increase (decrease)	18.00%
Acquired Loan [Member]
Loans	$ 467,575,000	$ 494,072,000
Percent of portfolio	100.00%	100.00%
Period increase (decrease)	(5.40%)
Acquired Loan [Member] | Commercial Portfolio Segment [Member]
Loans	$ 319,939,000	$ 336,449,000
Percent of portfolio	68.40%	68.10%
Period increase (decrease)	(4.90%)
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans	$ 71,993,000	$ 77,132,000
Percent of portfolio	15.40%	15.60%
Period increase (decrease)	(6.70%)
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Loans	$ 8,083,000	$ 8,309,000
Percent of portfolio	1.70%	1.70%
Period increase (decrease)	(2.70%)
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Loans	$ 83,472,000	$ 86,955,000
Percent of portfolio	17.90%	17.60%
Period increase (decrease)	(4.00%)
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Loans	$ 90,206,000	$ 96,215,000
Percent of portfolio	19.30%	19.50%
Period increase (decrease)	(6.20%)
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Loans	$ 66,185,000	$ 67,838,000
Percent of portfolio	14.10%	13.70%
Period increase (decrease)	(2.40%)
Acquired Loan [Member] | Retail Portfolio Segment [Member]
Loans	$ 147,636,000	$ 157,623,000
Percent of portfolio	31.60%	31.90%
Period increase (decrease)	(6.30%)
Acquired Loan [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Loans	$ 43,085,000	$ 48,216,000
Percent of portfolio	9.20%	9.80%
Period increase (decrease)	(10.60%)
Acquired Loan [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Loans	$ 104,551,000	$ 109,407,000
Percent of portfolio	22.40%	22.10%
Period increase (decrease)	(4.40%)