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	6 Months Ended		12 Months Ended
	Jun. 30, 2013		Dec. 31, 2012
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	$ 996,804		$ 800,091
Gross Unrealized Gains	20,861		27,143
Gross Unrealized Losses	(12,777)		(1,598)
Fair Value	1,004,888		825,636
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	3,511		3,520
Gross Unrealized Gains	23		38
Fair Value	3,534		3,558
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	38,699		49,335
Gross Unrealized Gains	49		207
Gross Unrealized Losses	(367)		(17)
Fair Value	38,381		49,525
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	39,532		53,078
Gross Unrealized Gains	2,089		3,855
Gross Unrealized Losses	(11)		(1)
Fair Value	41,610		56,932
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	3,716		4,076
Gross Unrealized Gains	73		69
Fair Value	3,789		4,145
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	191,367		200,769
Gross Unrealized Gains	7,338		14,730
Gross Unrealized Losses	(278)		(252)
Fair Value	198,427		215,247
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	285,670		219,613
Gross Unrealized Gains	918		1,786
Gross Unrealized Losses	(8,790)		(294)
Fair Value	277,798		221,105
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	15,328		16,130
Gross Unrealized Gains			18
Gross Unrealized Losses	(125)		(143)
Fair Value	15,203		16,005
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	824	[1],[2]	824	[1],[2]
Gross Unrealized Gains	7,204	[1],[2]	2,061	[1],[2]
Gross Unrealized Losses		[1],[2]	(5)	[1],[2]
Fair Value	8,028	[1],[2]	2,880	[1],[2]
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	416,108		250,655
Gross Unrealized Gains	2,279		3,009
Gross Unrealized Losses	(3,074)		(826)
Fair Value	415,313		252,838
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	2,049		2,091
Gross Unrealized Gains	888		1,370
Gross Unrealized Losses	(132)		(60)
Fair Value	$ 2,805		$ 3,401

[1] Federal Home Loan Mortgage Corporation

[2] Federal National Mortgage Association