Note 2 - Investment Securities (Details) - Amortized Cost, Unrealized Gains and Losses, and Estimated Market Value of Held To Maturity Investment Securities Portfolio (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Note 2 - Investment Securities (Details) - Amortized Cost, Unrealized Gains and Losses, and Estimated Market Value of Held To Maturity Investment Securities Portfolio [Line Items]
Amortized Cost	$ 1,132,299	$ 1,156,041
Gross Unrealized Gains	8,274	30,322
Gross Unrealized Losses	(27,897)	(1,806)
Estimated Market Value	1,112,676	1,184,557
US Government-sponsored Enterprises Debt Securities [Member]
Note 2 - Investment Securities (Details) - Amortized Cost, Unrealized Gains and Losses, and Estimated Market Value of Held To Maturity Investment Securities Portfolio [Line Items]
Amortized Cost	1,601	3,232
Gross Unrealized Gains		43
Gross Unrealized Losses	(4)
Estimated Market Value	1,597	3,275
Residential Mortgage Backed Securities [Member]
Note 2 - Investment Securities (Details) - Amortized Cost, Unrealized Gains and Losses, and Estimated Market Value of Held To Maturity Investment Securities Portfolio [Line Items]
Amortized Cost	65,076	72,807
Gross Unrealized Gains	854	2,090
Gross Unrealized Losses	(624)	(10)
Estimated Market Value	65,306	74,887
US States and Political Subdivisions Debt Securities [Member]
Note 2 - Investment Securities (Details) - Amortized Cost, Unrealized Gains and Losses, and Estimated Market Value of Held To Maturity Investment Securities Portfolio [Line Items]
Amortized Cost	756,707	680,802
Gross Unrealized Gains	6,211	23,004
Gross Unrealized Losses	(21,667)	(1,235)
Estimated Market Value	741,251	702,571
Residential Collateralized Mortgage Obligations [Member]
Note 2 - Investment Securities (Details) - Amortized Cost, Unrealized Gains and Losses, and Estimated Market Value of Held To Maturity Investment Securities Portfolio [Line Items]
Amortized Cost	308,915	399,200
Gross Unrealized Gains	1,209	5,185
Gross Unrealized Losses	(5,602)	(561)
Estimated Market Value	$ 304,522	$ 403,824