Note 3 - Loans and Allowance for Loan Losses - Loans by Credit Quality Indicators (Details) - USD ($)	Jun. 30, 2018	Dec. 31, 2017
Loans	$ 2,636,856,000	$ 2,558,552,000
Originated Loan [Member]
Loans	2,296,204,000	2,169,957,000
Acquired Loan [Member]
Loans	340,652,000	388,595,000
Commercial Portfolio Segment [Member]
Loans	2,261,970,000	2,203,568,000
Commercial Portfolio Segment [Member] | Originated Loan [Member]
Loans	2,027,193,000	1,934,228,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member]
Loans	234,777,000	269,340,000
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans	776,995,000	753,764,000
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Originated Loan [Member]
Loans	712,138,000	680,805,000
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Acquired Loan [Member]
Loans	64,857,000	72,959,000
Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Loans	37,868,000	29,873,000
Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member] | Originated Loan [Member]
Loans	32,031,000	23,682,000
Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member] | Acquired Loan [Member]
Loans	5,837,000	6,191,000
Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Loans	533,075,000	526,328,000
Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member] | Originated Loan [Member]
Loans	477,696,000	456,065,000
Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member] | Acquired Loan [Member]
Loans	55,379,000	70,263,000
Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Loans	818,376,000	791,685,000
Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member] | Originated Loan [Member]
Loans	743,102,000	708,824,000
Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member] | Acquired Loan [Member]
Loans	75,274,000	82,861,000
Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Loans	95,656,000	101,918,000
Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Originated Loan [Member]
Loans	62,226,000	64,852,000
Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Acquired Loan [Member]
Loans	33,430,000	37,066,000
Grades 1-4 [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Originated Loan [Member]
Loans	485,217,000	469,537,000
Grades 1-4 [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Acquired Loan [Member]
Loans	40,786,000	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	19,188,000	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	1,425,000	1,446,000
Grades 1-4 [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member] | Originated Loan [Member]
Loans	317,954,000	326,700,000
Grades 1-4 [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member] | Acquired Loan [Member]
Loans	25,930,000	28,706,000
Grades 1-4 [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member] | Originated Loan [Member]
Loans	550,444,000	559,388,000
Grades 1-4 [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member] | Acquired Loan [Member]
Loans	56,037,000	52,674,000
Grades 1-4 [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Originated Loan [Member]
Loans	39,788,000	42,951,000
Grades 1-4 [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Acquired Loan [Member]
Loans	17,246,000	17,499,000
Grades 5-7 [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Originated Loan [Member]
Loans	207,645,000	189,851,000
Grades 5-7 [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Acquired Loan [Member]
Loans	23,788,000	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	12,744,000	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	4,389,000	4,745,000
Grades 5-7 [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member] | Originated Loan [Member]
Loans	146,819,000	123,024,000
Grades 5-7 [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member] | Acquired Loan [Member]
Loans	27,543,000	39,565,000
Grades 5-7 [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member] | Originated Loan [Member]
Loans	192,658,000	149,135,000
Grades 5-7 [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member] | Acquired Loan [Member]
Loans	19,160,000	30,102,000
Grades 5-7 [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Originated Loan [Member]
Loans	22,015,000	21,552,000
Grades 5-7 [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Acquired Loan [Member]
Loans	16,021,000	19,212,000
Grades 8-9 [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Originated Loan [Member]
Loans	19,276,000	21,417,000
Grades 8-9 [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Acquired Loan [Member]
Loans	283,000	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	99,000	35,000
Grades 8-9 [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member] | Acquired Loan [Member]
Loans	23,000	0
Grades 8-9 [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member] | Originated Loan [Member]
Loans	12,923,000	6,341,000
Grades 8-9 [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member] | Acquired Loan [Member]
Loans	1,906,000	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	77,000	85,000
Grades 8-9 [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Originated Loan [Member]
Loans	423,000	349,000
Grades 8-9 [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Acquired Loan [Member]
Loans	$ 163,000	$ 355,000