Note 3 - Loans and Allowance for Loan Losses - Loans by Credit Quality Indicators (Details) - USD ($)	Mar. 31, 2018	Dec. 31, 2017
Loans	$ 2,551,204,000	$ 2,558,552,000
Originated Loan [Member]
Loans	2,191,851,000	2,169,957,000
Acquired Loan [Member]
Loans	359,353,000	388,595,000
Commercial Portfolio Segment [Member]
Loans	2,193,029,000	2,203,568,000
Commercial Portfolio Segment [Member] \| Originated Loan [Member]
Loans	1,946,966,000	1,934,228,000
Commercial Portfolio Segment [Member] \| Acquired Loan [Member]
Loans	246,063,000	269,340,000
Commercial Portfolio Segment [Member] \| Commercial and Industrial [Member]
Loans	739,805,000	753,764,000
Commercial Portfolio Segment [Member] \| Commercial and Industrial [Member] \| Originated Loan [Member]
Loans	675,188,000	680,805,000
Commercial Portfolio Segment [Member] \| Commercial and Industrial [Member] \| Acquired Loan [Member]
Loans	64,617,000	72,959,000
Commercial Portfolio Segment [Member] \| Vacant Land and Land Development and Residential Construction Loan [Member]
Loans	31,438,000	29,873,000
Commercial Portfolio Segment [Member] \| Vacant Land and Land Development and Residential Construction Loan [Member] \| Originated Loan [Member]
Loans	25,514,000	23,682,000
Commercial Portfolio Segment [Member] \| Vacant Land and Land Development and Residential Construction Loan [Member] \| Acquired Loan [Member]
Loans	5,924,000	6,191,000
Commercial Portfolio Segment [Member] \| Real Estate Owner Occupied Loan [Member]
Loans	531,152,000	526,328,000
Commercial Portfolio Segment [Member] \| Real Estate Owner Occupied Loan [Member] \| Originated Loan [Member]
Loans	468,777,000	456,065,000
Commercial Portfolio Segment [Member] \| Real Estate Owner Occupied Loan [Member] \| Acquired Loan [Member]
Loans	62,375,000	70,263,000
Commercial Portfolio Segment [Member] \| Real Estate Non Owner Occupied Loan [Member]
Loans	794,206,000	791,685,000
Commercial Portfolio Segment [Member] \| Real Estate Non Owner Occupied Loan [Member] \| Originated Loan [Member]
Loans	715,725,000	708,824,000
Commercial Portfolio Segment [Member] \| Real Estate Non Owner Occupied Loan [Member] \| Acquired Loan [Member]
Loans	78,481,000	82,861,000
Commercial Portfolio Segment [Member] \| Real Estate Multi Family and Residential Rental Loan [Member]
Loans	96,428,000	101,918,000
Commercial Portfolio Segment [Member] \| Real Estate Multi Family and Residential Rental Loan [Member] \| Originated Loan [Member]
Loans	61,762,000	64,852,000
Commercial Portfolio Segment [Member] \| Real Estate Multi Family and Residential Rental Loan [Member] \| Acquired Loan [Member]
Loans	34,666,000	37,066,000
Grades 1-4 [Member] \| Commercial Portfolio Segment [Member] \| Commercial and Industrial [Member] \| Originated Loan [Member]
Loans	468,826,000	469,537,000
Grades 1-4 [Member] \| Commercial Portfolio Segment [Member] \| Commercial and Industrial [Member] \| Acquired Loan [Member]
Loans	39,543,000	46,263,000
Grades 1-4 [Member] \| Commercial Portfolio Segment [Member] \| Vacant Land and Land Development and Residential Construction Loan [Member] \| Originated Loan [Member]
Loans	17,645,000	15,090,000
Grades 1-4 [Member] \| Commercial Portfolio Segment [Member] \| Vacant Land and Land Development and Residential Construction Loan [Member] \| Acquired Loan [Member]
Loans	1,412,000	1,446,000
Grades 1-4 [Member] \| Commercial Portfolio Segment [Member] \| Real Estate Owner Occupied Loan [Member] \| Originated Loan [Member]
Loans	313,933,000	326,700,000
Grades 1-4 [Member] \| Commercial Portfolio Segment [Member] \| Real Estate Owner Occupied Loan [Member] \| Acquired Loan [Member]
Loans	28,823,000	28,706,000
Grades 1-4 [Member] \| Commercial Portfolio Segment [Member] \| Real Estate Non Owner Occupied Loan [Member] \| Originated Loan [Member]
Loans	564,093,000	559,388,000
Grades 1-4 [Member] \| Commercial Portfolio Segment [Member] \| Real Estate Non Owner Occupied Loan [Member] \| Acquired Loan [Member]
Loans	54,951,000	52,674,000
Grades 1-4 [Member] \| Commercial Portfolio Segment [Member] \| Real Estate Multi Family and Residential Rental Loan [Member] \| Originated Loan [Member]
Loans	39,571,000	42,951,000
Grades 1-4 [Member] \| Commercial Portfolio Segment [Member] \| Real Estate Multi Family and Residential Rental Loan [Member] \| Acquired Loan [Member]
Loans	17,376,000	17,499,000
Grades 5-7 [Member] \| Commercial Portfolio Segment [Member] \| Commercial and Industrial [Member] \| Originated Loan [Member]
Loans	187,118,000	189,851,000
Grades 5-7 [Member] \| Commercial Portfolio Segment [Member] \| Commercial and Industrial [Member] \| Acquired Loan [Member]
Loans	24,591,000	25,654,000
Grades 5-7 [Member] \| Commercial Portfolio Segment [Member] \| Vacant Land and Land Development and Residential Construction Loan [Member] \| Originated Loan [Member]
Loans	7,767,000	8,557,000
Grades 5-7 [Member] \| Commercial Portfolio Segment [Member] \| Vacant Land and Land Development and Residential Construction Loan [Member] \| Acquired Loan [Member]
Loans	4,512,000	4,745,000
Grades 5-7 [Member] \| Commercial Portfolio Segment [Member] \| Real Estate Owner Occupied Loan [Member] \| Originated Loan [Member]
Loans	140,088,000	123,024,000
Grades 5-7 [Member] \| Commercial Portfolio Segment [Member] \| Real Estate Owner Occupied Loan [Member] \| Acquired Loan [Member]
Loans	30,940,000	39,565,000
Grades 5-7 [Member] \| Commercial Portfolio Segment [Member] \| Real Estate Non Owner Occupied Loan [Member] \| Originated Loan [Member]
Loans	151,632,000	149,135,000
Grades 5-7 [Member] \| Commercial Portfolio Segment [Member] \| Real Estate Non Owner Occupied Loan [Member] \| Acquired Loan [Member]
Loans	23,448,000	30,102,000
Grades 5-7 [Member] \| Commercial Portfolio Segment [Member] \| Real Estate Multi Family and Residential Rental Loan [Member] \| Originated Loan [Member]
Loans	21,709,000	21,552,000
Grades 5-7 [Member] \| Commercial Portfolio Segment [Member] \| Real Estate Multi Family and Residential Rental Loan [Member] \| Acquired Loan [Member]
Loans	17,132,000	19,212,000
Grades 8-9 [Member] \| Commercial Portfolio Segment [Member] \| Commercial and Industrial [Member] \| Originated Loan [Member]
Loans	19,244,000	21,417,000
Grades 8-9 [Member] \| Commercial Portfolio Segment [Member] \| Commercial and Industrial [Member] \| Acquired Loan [Member]
Loans	483,000	1,042,000
Grades 8-9 [Member] \| Commercial Portfolio Segment [Member] \| Vacant Land and Land Development and Residential Construction Loan [Member] \| Originated Loan [Member]
Loans	102,000	35,000
Grades 8-9 [Member] \| Commercial Portfolio Segment [Member] \| Vacant Land and Land Development and Residential Construction Loan [Member] \| Acquired Loan [Member]
Loans	0	0
Grades 8-9 [Member] \| Commercial Portfolio Segment [Member] \| Real Estate Owner Occupied Loan [Member] \| Originated Loan [Member]
Loans	14,756,000	6,341,000
Grades 8-9 [Member] \| Commercial Portfolio Segment [Member] \| Real Estate Owner Occupied Loan [Member] \| Acquired Loan [Member]
Loans	2,612,000	1,992,000
Grades 8-9 [Member] \| Commercial Portfolio Segment [Member] \| Real Estate Non Owner Occupied Loan [Member] \| Originated Loan [Member]
Loans	0	301,000
Grades 8-9 [Member] \| Commercial Portfolio Segment [Member] \| Real Estate Non Owner Occupied Loan [Member] \| Acquired Loan [Member]
Loans	82,000	85,000
Grades 8-9 [Member] \| Commercial Portfolio Segment [Member] \| Real Estate Multi Family and Residential Rental Loan [Member] \| Originated Loan [Member]
Loans	482,000	349,000
Grades 8-9 [Member] \| Commercial Portfolio Segment [Member] \| Real Estate Multi Family and Residential Rental Loan [Member] \| Acquired Loan [Member]
Loans	$ 158,000	$ 355,000

Note 3 - Loans and Allowance for Loan Losses - Loans by Credit Quality Indicators (Details) - USD ($)

Mar. 31, 2018

Dec. 31, 2017

Loans

$ 2,551,204,000

$ 2,558,552,000

Originated Loan [Member]

Loans

2,191,851,000

2,169,957,000

Acquired Loan [Member]

Loans