Note 4 - Loans and Allowance for Loan Losses (Details)		3 Months Ended		6 Months Ended		12 Months Ended
		Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)	Mar. 31, 2015 USD ($)
Note 4 - Loans and Allowance for Loan Losses (Details) [Line Items]
Loans and Leases Receivable, Gross		$ 4,810,000,000		$ 4,810,000,000		$ 2,740,000,000
Impaired Financing Receivable, Recorded Investment		16,357,000		16,357,000		14,669,000
Impaired Financing Receivable, Related Allowance		2,012,000		2,012,000		2,075,000
Impaired Financing Receivable, Interest Income, Accrual Method		300,000	$ 158,000	549,000	$ 364,000
Impaired Financing Receivable, Average Recorded Investment		$ 16,638,000	$ 18,743,000	$ 15,981,000	$ 18,601,000
Financing Receivable, Modifications, Number of Contracts		5	1	7	2
Financing Receivable, Modifications, Pre-Modification Recorded Investment		$ 380,000	$ 599,000	$ 728,000	$ 1,630,000
Mortgage Loans in Process of Foreclosure, Amount		1,537,000		1,537,000
Real Estate Acquired Through Foreclosure		42,666,000		42,666,000		44,856,000
Acquired Impaired Loans, Carrying Value	[1]	2,201,427,000		2,201,427,000		682,913,000
Loans And Leases Receivable Classified		29,800,000		29,800,000		16,600,000
Covered Purchased Impaired Loans, Allowance		1,000,000		1,000,000		1,000,000
Provision for Loan Losses, Net of FDIC Loss Share Adjustments						400,000
Provision for Loan and Lease Losses		3,006,000	$ 1,602,000	4,177,000	$ 2,510,000
Loans and Leases Receivable, Allowance		30,567,000		$ 30,567,000		29,028,000
Risk Ratings 6,7, and 8 [Member]
Note 4 - Loans and Allowance for Loan Losses (Details) [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts				0	0
Loans And Leases Receivable Classified		102,100,000		$ 102,100,000		82,100,000
Liberty, Community First, Metropolitan and Delta Trust Acquisitions [Member]
Note 4 - Loans and Allowance for Loan Losses (Details) [Line Items]
Acquired Impaired Loans, Carrying Value		32,900,000		32,900,000		22,300,000
OREO Secured by Residential Real Estate Properties [Member]
Note 4 - Loans and Allowance for Loan Losses (Details) [Line Items]
Real Estate Acquired Through Foreclosure		$ 4,599,000		4,599,000
OREO Received in Full or Partial Satisfaction of Loans [Member] | Commerical Real Estate and Residential Real Estate [Member]
Note 4 - Loans and Allowance for Loan Losses (Details) [Line Items]
Financing Receivable, Modifications, Pre-Modification Recorded Investment				$ 4,756,500	$ 9,268,321
Restructured During Current Period [Member]
Note 4 - Loans and Allowance for Loan Losses (Details) [Line Items]
Financing Receivable, Modifications, Number of Contracts		5	1	7	2
Financing Receivable, Modifications, Pre-Modification Recorded Investment		$ 380,000	$ 599,000		$ 1,630,000
Restructured Loan [Member]
Note 4 - Loans and Allowance for Loan Losses (Details) [Line Items]
Financing Receivable, Modifications, Pre-Modification Recorded Investment				$ 728,000
Acquired Loans [Member]
Note 4 - Loans and Allowance for Loan Losses (Details) [Line Items]
Loans and Leases Receivable, Gross		2,108,306,000		2,108,306,000		575,980,000
Provision for Loan and Lease Losses		604,000		604,000
Allowance for Loan and Lease Losses, Write-offs				604,000
Loans and Leases Receivable, Allowance		0		0
Loans and Leases Receivable, Allowance, Covered		954,000		954,000		954,000	$ 954,000
Loans, Including Acquired Loans [Member]
Note 4 - Loans and Allowance for Loan Losses (Details) [Line Items]
Loans and Leases Receivable, Allowance		$ 31,521,000		$ 31,521,000		$ 29,982,000	$ 30,137,000

[1] Loans acquired include $93.1 million and $106.9 million (each net of $1.0 million allowance) of loans covered by FDIC loss share agreements at June 30, 2015 and December 31, 2014, respectively.