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	Sep. 30, 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	$ 1,374,368		$ 1,071,691
Gross Unrealized Gains	31,055		24,946
Gross Unrealized Losses	(14,061)		(17,256)
Fair Value	1,391,362		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	10		9
Gross Unrealized Losses			(3)
Fair Value	3,509		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	442,482		131,080
Gross Unrealized Gains	214		75
Gross Unrealized Losses	(1,160)		(663)
Fair Value	441,536		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	26,574		32,428
Gross Unrealized Gains	1,799		1,763
Gross Unrealized Losses	(20)		(15)
Fair Value	28,353		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	3,021		3,411
Gross Unrealized Gains	7		19
Gross Unrealized Losses	(7)		(5)
Fair Value	3,021		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	176,614		186,082
Gross Unrealized Gains	10,203		5,627
Gross Unrealized Losses	(197)		(323)
Fair Value	186,620		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	240,091		266,890
Gross Unrealized Gains	594		730
Gross Unrealized Losses	(11,400)		(14,724)
Fair Value	229,285		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	8,674		14,653
Gross Unrealized Gains			3
Gross Unrealized Losses	(35)		(101)
Fair Value	8,639		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	[1],[2]	804
Gross Unrealized Gains	13,798	[1],[2]	12,568
Gross Unrealized Losses		[1],[2]
Fair Value	14,602	[1],[2]	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	470,570		430,794
Gross Unrealized Gains	3,674		2,901
Gross Unrealized Losses	(1,106)		(1,264)
Fair Value	473,138		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	756		1,251
Gross Unrealized Losses	(136)		(158)
Fair Value	$ 2,659		$ 3,142

[1] Federal Home Loan Mortgage Corporation

[2] Federal National Mortgage Association