Note 6 - Investment Securities (Details) (USD $)	3 Months Ended	6 Months Ended
	Mar. 31, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Note 6 - Investment Securities (Details) [Line Items]
Investment Securities		$ 1,340,000,000		$ 1,590,000,000
Held-to-maturity Securities, Transferred Security, at Carrying Value	722,500,000
Held-to-maturity Securities, Transferred Security, Unrealized Gain (Loss)	40,500,000
Proceeds from Sale of Mortgage Backed Securities (MBS) categorized as Available-for-sale		386,500,000	113,600,000
Proceeds from Maturities, Prepayments and Calls of Mortgage Backed Securities (MBS)		39,600,000	179,000,000
Proceeds From Sales and Repayments of Other Investment Securities		80,400,000	440,100,000
Proceeds From Maturities Repayments And Calls Of Held For Investment		135,800,000	80,100,000
Realized Gain From Sale and Call of Investment Securities		12,800,000	18,500,000
Realized Loss From Sale and Call of Investment Securities		6,300,000	0
Temporarily Impaired Securities As Percentage of Investment Securities		60.20%
Percentage of Unrealized Losses for Securities with Unrealized Losses for Less Than Twelve Months		0.003%
Percentage of Unrealized Losses for Securities with Unrealized Losses for Greater than Twelve Months		3.60%
Pledged Investment Securities		849,100,000		926,500,000
Collateralized Mortgage Backed Securities [Member]
Note 6 - Investment Securities (Details) [Line Items]
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax		24,900,000
Corporate Bonds Issued By Financial Institutions [Member]
Note 6 - Investment Securities (Details) [Line Items]
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax		$ 1,400,000