Note 3 - Investment Securities (Details) - Amortized Cost, Unrealized Gains and Losses Accumulated in Other Comprehensive income, and Fair Value - Available for Sale 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 Accumulated in Other Comprehensive income, and Fair Value - Available for Sale Investment Securities Portfolio [Line Items]
Amortized Cost	$ 1,224,775	$ 1,071,691
Gross Unrealized Gains	30,420	24,946
Gross Unrealized Losses	(14,907)	(17,256)
Fair Value	1,240,288	1,079,381
US Treasury Securities [Member]
Note 3 - Investment Securities (Details) - Amortized Cost, Unrealized Gains and Losses Accumulated in Other Comprehensive income, and Fair Value - Available for Sale Investment Securities Portfolio [Line Items]
Amortized Cost	3,499	3,500
Gross Unrealized Gains	9	9
Gross Unrealized Losses		(3)
Fair Value	3,508	3,506
US Government-sponsored Enterprises Debt Securities [Member]
Note 3 - Investment Securities (Details) - Amortized Cost, Unrealized Gains and Losses Accumulated in Other Comprehensive income, and Fair Value - Available for Sale Investment Securities Portfolio [Line Items]
Amortized Cost	329,589	131,080
Gross Unrealized Gains	108	75
Gross Unrealized Losses	(1,387)	(663)
Fair Value	328,310	130,492
Residential Mortgage Backed Securities [Member]
Note 3 - Investment Securities (Details) - Amortized Cost, Unrealized Gains and Losses Accumulated in Other Comprehensive income, and Fair Value - Available for Sale Investment Securities Portfolio [Line Items]
Amortized Cost	30,154	32,428
Gross Unrealized Gains	1,791	1,763
Gross Unrealized Losses	(18)	(15)
Fair Value	31,927	34,176
Commercial Mortgage Backed Securities [Member]
Note 3 - Investment Securities (Details) - Amortized Cost, Unrealized Gains and Losses Accumulated in Other Comprehensive income, and Fair Value - Available for Sale Investment Securities Portfolio [Line Items]
Amortized Cost	3,216	3,411
Gross Unrealized Gains	10	19
Gross Unrealized Losses	(5)	(5)
Fair Value	3,221	3,425
US States and Political Subdivisions Debt Securities [Member]
Note 3 - Investment Securities (Details) - Amortized Cost, Unrealized Gains and Losses Accumulated in Other Comprehensive income, and Fair Value - Available for Sale Investment Securities Portfolio [Line Items]
Amortized Cost	180,011	186,082
Gross Unrealized Gains	7,635	5,627
Gross Unrealized Losses	(222)	(323)
Fair Value	187,424	191,386
Residential Collateralized Mortgage Obligations [Member]
Note 3 - Investment Securities (Details) - Amortized Cost, Unrealized Gains and Losses Accumulated in Other Comprehensive income, and Fair Value - Available for Sale Investment Securities Portfolio [Line Items]
Amortized Cost	259,615	266,890
Gross Unrealized Gains	674	730
Gross Unrealized Losses	(12,460)	(14,724)
Fair Value	247,829	252,896
Asset-backed Securities [Member]
Note 3 - Investment Securities (Details) - Amortized Cost, Unrealized Gains and Losses Accumulated in Other Comprehensive income, and Fair Value - Available for Sale Investment Securities Portfolio [Line Items]
Amortized Cost	9,322	14,653
Gross Unrealized Gains	5	3
Gross Unrealized Losses	(56)	(101)
Fair Value	9,271	14,555
FHLMC And FNMA Stock [Member]
Note 3 - Investment Securities (Details) - Amortized Cost, Unrealized Gains and Losses Accumulated in Other Comprehensive income, and Fair Value - Available for Sale Investment Securities Portfolio [Line Items]
Amortized Cost	804	804
Gross Unrealized Gains	16,241	12,568
Fair Value	17,045	13,372
Domestic Corporate Debt Securities [Member]
Note 3 - Investment Securities (Details) - Amortized Cost, Unrealized Gains and Losses Accumulated in Other Comprehensive income, and Fair Value - Available for Sale Investment Securities Portfolio [Line Items]
Amortized Cost	406,526	430,794
Gross Unrealized Gains	3,180	2,901
Gross Unrealized Losses	(609)	(1,264)
Fair Value	409,097	432,431
Other Securities [Member]
Note 3 - Investment Securities (Details) - Amortized Cost, Unrealized Gains and Losses Accumulated in Other Comprehensive income, and Fair Value - Available for Sale Investment Securities Portfolio [Line Items]
Amortized Cost	2,039	2,049
Gross Unrealized Gains	767	1,251
Gross Unrealized Losses	(150)	(158)
Fair Value	$ 2,656	$ 3,142