Note 5 - Loans Acquired (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2015	Sep. 30, 2014
Note 5 - Loans Acquired (Details) [Line Items]
Allowance for Loan and Lease Losses, Loans Acquired	$ 0	$ 0
Impaired Loans Acquired Cash Flows Expected to be Collected Including Interest as of Acquisition Date	742,100,000
Certain Loans Acquired In Transfer Accretable Yield Adjustment	17,000,000
FDIC Indemnification Asset Accretable Yield Adjustment	10,600,000
Covered Purchased Impaired Loans, Allowance	1,000,000
Purchased Credit Impaired Loans [Member] | Metropolitan [Member]
Note 5 - Loans Acquired (Details) [Line Items]
Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed Other Noncurrent Assets Loans Acquired Not Covered by FDIC Loss Share		28,400,000		3,500,000
Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed Other Noncurrent Assets Loans Acquired Gross		52,800,000		10,700,000
Loans Acquired Discount		24,500,000		7,200,000
Scenario, Forecast [Member]
Note 5 - Loans Acquired (Details) [Line Items]
Certain Loans Acquired In Transfer Accretable Yield Adjustment Current Year Increase Decrease			9,100,000
FDIC Indemnification Asset Accretable Yield Adjustment Current Year Increase Decrease			(7,900,000)
Net Addition to Pre-tax Income Due to Remaining Accretable Yield Adjustments			1,200,000
Metropolitan [Member]
Note 5 - Loans Acquired (Details) [Line Items]
Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed Other Noncurrent Assets Loans Acquired Not Covered by FDIC Loss Share		429,000,000		308,200,000
Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed Other Noncurrent Assets Loans Acquired Gross		442,000,000		316,100,000
Loans Acquired Discount		13,000,000		7,900,000
Acquired Loans, Covered By FDIC Loss Share Agreements	106,900,000	146,700,000
Allowance for Loan and Lease Losses, Loans Acquired	1,000,000
Metropolitan, Truman, and Excel [Member]
Note 5 - Loans Acquired (Details) [Line Items]
Covered Impaired Loans Acquired Estimates of Contractually Required Payments Receivable Including Interest	$ 836,000,000