Note 3 - Loans and Allowance for Loan Losses (Details) - Loans by Credit Quality Indicators - USD ($)	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	$ 2,295,668,000	$ 2,277,727,000
Originated Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	1,687,476,000	1,616,587,000	$ 1,328,713,000
Acquired Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	608,192,000	661,140,000
Commercial Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	1,974,450,000	1,946,696,000
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	714,612,000	696,303,000
Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	39,630,000	45,120,000
Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	441,662,000	445,919,000
Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	666,013,000	644,351,000
Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	112,533,000	115,003,000
Commercial Portfolio Segment [Member] | Originated Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	1,562,777,000	1,493,516,000	$ 1,230,841,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	613,570,000	577,872,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Commercial and Industrial [Member] | Grade 1 - 4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	417,049,000	417,120,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Commercial and Industrial [Member] | Grade 5 - 7 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	196,431,000	160,454,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Commercial and Industrial [Member] | Grade 8 - 9 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	90,000	298,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	28,451,000	30,138,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member] | Grade 1 - 4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	16,694,000	18,118,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member] | Grade 5 - 7 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	11,617,000	10,365,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member] | Grade 8 - 9 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	140,000	1,655,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Owner Occupied Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	334,948,000	330,798,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Owner Occupied Loan [Member] | Grade 1 - 4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	231,625,000	230,629,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Owner Occupied Loan [Member] | Grade 5 - 7 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	101,552,000	98,332,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Owner Occupied Loan [Member] | Grade 8 - 9 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	1,771,000	1,837,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Non Owner Occupied Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	549,226,000	520,754,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Non Owner Occupied Loan [Member] | Grade 1 - 4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	434,645,000	400,350,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Non Owner Occupied Loan [Member] | Grade 5 - 7 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	114,581,000	120,404,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Non Owner Occupied Loan [Member] | Grade 8 - 9 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	0	0
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	36,582,000	33,954,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Grade 1 - 4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	19,947,000	19,121,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Grade 5 - 7 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	15,629,000	13,806,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Grade 8 - 9 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	1,006,000	1,027,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	411,673,000	453,180,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	101,042,000	118,431,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Commercial and Industrial [Member] | Grade 1 - 4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	51,717,000	67,978,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Commercial and Industrial [Member] | Grade 5 - 7 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	46,749,000	47,589,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Commercial and Industrial [Member] | Grade 8 - 9 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	2,576,000	2,864,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	11,179,000	14,982,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member] | Grade 1 - 4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	2,892,000	3,095,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member] | Grade 5 - 7 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	7,811,000	11,364,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member] | Grade 8 - 9 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	476,000	523,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Owner Occupied Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	106,714,000	115,121,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Owner Occupied Loan [Member] | Grade 1 - 4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	43,806,000	45,807,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Owner Occupied Loan [Member] | Grade 5 - 7 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	58,971,000	63,563,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Owner Occupied Loan [Member] | Grade 8 - 9 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	3,937,000	5,751,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Non Owner Occupied Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	116,787,000	123,597,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Non Owner Occupied Loan [Member] | Grade 1 - 4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	66,096,000	71,197,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Non Owner Occupied Loan [Member] | Grade 5 - 7 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	48,792,000	50,066,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Non Owner Occupied Loan [Member] | Grade 8 - 9 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	1,899,000	2,334,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	75,951,000	81,049,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Grade 1 - 4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	42,159,000	44,763,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Grade 5 - 7 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	33,071,000	35,288,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Grade 8 - 9 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, credit exposure	$ 721,000	$ 998,000