Note 3 - Loans and Allowance for Loan Losses - Loans by Credit Quality Indicators (Details) - USD ($)	Sep. 30, 2017	Dec. 31, 2016
Loans	$ 2,554,272,000	$ 2,378,620,000
Originated Loan [Member]
Loans	2,133,766,000	1,884,548,000
Acquired Loan [Member]
Loans	420,506,000	494,072,000
Commercial Portfolio Segment [Member]
Loans	2,214,822,000	2,065,347,000
Commercial Portfolio Segment [Member] | Originated Loan [Member]
Loans	1,922,998,000	1,728,898,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member]
Loans	291,824,000	336,449,000
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans	776,563,000	713,903,000
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Originated Loan [Member]
Loans	710,699,000	636,771,000
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Acquired Loan [Member]
Loans	65,864,000	77,132,000
Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Loans	28,575,000	34,828,000
Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member] | Originated Loan [Member]
Loans	21,272,000	26,519,000
Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member] | Acquired Loan [Member]
Loans	7,303,000	8,309,000
Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Loans	485,347,000	450,464,000
Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member] | Originated Loan [Member]
Loans	411,367,000	363,509,000
Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member] | Acquired Loan [Member]
Loans	73,980,000	86,955,000
Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Loans	805,167,000	748,269,000
Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member] | Originated Loan [Member]
Loans	721,304,000	652,054,000
Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member] | Acquired Loan [Member]
Loans	83,863,000	96,215,000
Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Loans	119,170,000	117,883,000
Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Originated Loan [Member]
Loans	58,356,000	50,045,000
Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Acquired Loan [Member]
Loans	60,814,000	67,838,000
Grades 1-4 [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Originated Loan [Member]
Loans	534,639,000	440,219,000
Grades 1-4 [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Acquired Loan [Member]
Loans	38,477,000	40,911,000
Grades 1-4 [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member] | Originated Loan [Member]
Loans	13,017,000	16,378,000
Grades 1-4 [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member] | Acquired Loan [Member]
Loans	1,536,000	1,887,000
Grades 1-4 [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member] | Originated Loan [Member]
Loans	312,650,000	238,890,000
Grades 1-4 [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member] | Acquired Loan [Member]
Loans	29,429,000	36,246,000
Grades 1-4 [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member] | Originated Loan [Member]
Loans	573,763,000	542,294,000
Grades 1-4 [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member] | Acquired Loan [Member]
Loans	50,688,000	57,671,000
Grades 1-4 [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Originated Loan [Member]
Loans	37,127,000	29,793,000
Grades 1-4 [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Acquired Loan [Member]
Loans	36,523,000	39,574,000
Grades 5-7 [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Originated Loan [Member]
Loans	171,658,000	190,170,000
Grades 5-7 [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Acquired Loan [Member]
Loans	26,315,000	35,233,000
Grades 5-7 [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member] | Originated Loan [Member]
Loans	8,205,000	10,046,000
Grades 5-7 [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member] | Acquired Loan [Member]
Loans	4,831,000	6,164,000
Grades 5-7 [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member] | Originated Loan [Member]
Loans	95,973,000	123,517,000
Grades 5-7 [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member] | Acquired Loan [Member]
Loans	43,010,000	49,255,000
Grades 5-7 [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member] | Originated Loan [Member]
Loans	147,541,000	109,304,000
Grades 5-7 [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member] | Acquired Loan [Member]
Loans	32,161,000	37,040,000
Grades 5-7 [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Originated Loan [Member]
Loans	20,803,000	19,082,000
Grades 5-7 [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Acquired Loan [Member]
Loans	22,899,000	28,015,000
Grades 8-9 [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Originated Loan [Member]
Loans	4,402,000	6,382,000
Grades 8-9 [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Acquired Loan [Member]
Loans	1,072,000	988,000
Grades 8-9 [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member] | Originated Loan [Member]
Loans	50,000	95,000
Grades 8-9 [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member] | Acquired Loan [Member]
Loans	936,000	258,000
Grades 8-9 [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member] | Originated Loan [Member]
Loans	2,744,000	1,102,000
Grades 8-9 [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member] | Acquired Loan [Member]
Loans	1,541,000	1,454,000
Grades 8-9 [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member] | Originated Loan [Member]
Loans	0	456,000
Grades 8-9 [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member] | Acquired Loan [Member]
Loans	1,014,000	1,504,000
Grades 8-9 [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Originated Loan [Member]
Loans	426,000	1,170,000
Grades 8-9 [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Acquired Loan [Member]
Loans	$ 1,392,000	$ 249,000