Note 6 - Investment Securities (Details) (USD $)	3 Months Ended	9 Months Ended						3 Months Ended
	Mar. 31, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Sep. 30, 2014 Collateralized Mortgage Backed Securities [Member]	Dec. 31, 2013 Collateralized Mortgage Backed Securities [Member]	Sep. 30, 2014 Corporate Bonds Issued By Financial Institutions [Member]	Sep. 30, 2014 Preferred Stock of Government Sponsored Entities [Member]
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		458,400,000	348,700,000
Proceeds from Maturities, Prepayments and Calls of Mortgage Backed Securities (MBS)		54,700,000	237,900,000
Proceeds From Sales and Repayments of Other Investment Securities		84,900,000	555,200,000
Proceeds From Maturities Repayments And Calls Of Held For Investment		585,800,000	180,100,000
Realized Gain From Sale and Call of Investment Securities		17,100,000	27,200,000
Realized Loss From Sale and Call of Investment Securities		9,500,000	0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax		22,674,000		69,808,000	21,073,000	64,529,000	1,400,000
Temporarily Impaired Securities As Percentage of Investment Securities		66.30%
Percentage of Unrealized Losses for Securities with Unrealized Losses for Less Than Twelve Months		0.07%
Percentage of Unrealized Losses for Securities with Unrealized Losses for Greater than Twelve Months		3.50%
Other than Temporary Impairment Losses, Investments								820,000
Pledged Investment Securities		$ 703,600,000		$ 926,500,000