Note 3 - Investment Securities (Details) - Amortized Cost, Unrealized Gains and Losses, and Fair Value - Held to Maturity Investment Securities Portfolio (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Note 3 - Investment Securities (Details) - Amortized Cost, Unrealized Gains and Losses, and Fair Value - Held to Maturity Investment Securities Portfolio [Line Items]
Amortized Cost	$ 1,110,329	$ 1,132,299
Gross Unrealized Gains	9,891	8,274
Gross Unrealized Losses	(16,393)	(27,897)
Fair Value	1,103,827	1,112,676
US Government-sponsored Enterprises Debt Securities [Member]
Note 3 - Investment Securities (Details) - Amortized Cost, Unrealized Gains and Losses, and Fair Value - Held to Maturity Investment Securities Portfolio [Line Items]
Amortized Cost	1,428	1,601
Gross Unrealized Losses	(4)	(4)
Fair Value	1,424	1,597
Residential Mortgage Backed Securities [Member]
Note 3 - Investment Securities (Details) - Amortized Cost, Unrealized Gains and Losses, and Fair Value - Held to Maturity Investment Securities Portfolio [Line Items]
Amortized Cost	63,048	65,076
Gross Unrealized Gains	855	854
Gross Unrealized Losses	(388)	(624)
Fair Value	63,515	65,306
US States and Political Subdivisions Debt Securities [Member]
Note 3 - Investment Securities (Details) - Amortized Cost, Unrealized Gains and Losses, and Fair Value - Held to Maturity Investment Securities Portfolio [Line Items]
Amortized Cost	748,520	756,707
Gross Unrealized Gains	7,414	6,211
Gross Unrealized Losses	(11,409)	(21,667)
Fair Value	744,525	741,251
Residential Collateralized Mortgage Obligations [Member]
Note 3 - Investment Securities (Details) - Amortized Cost, Unrealized Gains and Losses, and Fair Value - Held to Maturity Investment Securities Portfolio [Line Items]
Amortized Cost	297,333	308,915
Gross Unrealized Gains	1,622	1,209
Gross Unrealized Losses	(4,592)	(5,602)
Fair Value	$ 294,363	$ 304,522