Note 6 - Debt and Equity Securities (Details) - Available for Sale Securities With Gross Unrealized Losses and Their Fair Value (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Note 6 - Debt and Equity Securities (Details) - Available for Sale Securities With Gross Unrealized Losses and Their Fair Value [Line Items]
Fair Value	$ 374,858	$ 601,100
Unrealized Losses	7,259	28,843
Less Than 12 Months - Fair Value	97,274	562,673
Less Than 12 Months - Unrealized Losses	846	23,116
12 Months or More - Fair Value	277,584	38,427
12 Months or More - Unrealized Losses	6,413	5,727
Corporate Debt Securities [Member]
Note 6 - Debt and Equity Securities (Details) - Available for Sale Securities With Gross Unrealized Losses and Their Fair Value [Line Items]
Fair Value	39,287	39,033
Unrealized Losses	714	967
Less Than 12 Months - Fair Value	9,573	39,033
Less Than 12 Months - Unrealized Losses	428	967
12 Months or More - Fair Value	29,714
12 Months or More - Unrealized Losses	286
Municipal [Member]
Note 6 - Debt and Equity Securities (Details) - Available for Sale Securities With Gross Unrealized Losses and Their Fair Value [Line Items]
Fair Value	8,810	100,875
Unrealized Losses	61	4,637
Less Than 12 Months - Fair Value	3,546	95,958
Less Than 12 Months - Unrealized Losses	11	4,187
12 Months or More - Fair Value	5,264	4,917
12 Months or More - Unrealized Losses	50	450
Other Debt Obligations [Member]
Note 6 - Debt and Equity Securities (Details) - Available for Sale Securities With Gross Unrealized Losses and Their Fair Value [Line Items]
Fair Value	292	6,337
Unrealized Losses	8	3,225
12 Months or More - Fair Value	292	6,337
12 Months or More - Unrealized Losses	8	3,225
Available For Sale Securities, Excluding Mortgage-Backed Securities [Member]
Note 6 - Debt and Equity Securities (Details) - Available for Sale Securities With Gross Unrealized Losses and Their Fair Value [Line Items]
Fair Value	48,389	146,245
Unrealized Losses	783	8,829
Less Than 12 Months - Fair Value	13,119	134,991
Less Than 12 Months - Unrealized Losses	439	5,154
12 Months or More - Fair Value	35,270	11,254
12 Months or More - Unrealized Losses	344	3,675
REMIC And CMO [Member]
Note 6 - Debt and Equity Securities (Details) - Available for Sale Securities With Gross Unrealized Losses and Their Fair Value [Line Items]
Fair Value	216,190	298,165
Unrealized Losses	4,627	11,830
Less Than 12 Months - Fair Value	77,382	279,743
Less Than 12 Months - Unrealized Losses	399	10,650
12 Months or More - Fair Value	138,808	18,422
12 Months or More - Unrealized Losses	4,228	1,180
GNMA [Member]
Note 6 - Debt and Equity Securities (Details) - Available for Sale Securities With Gross Unrealized Losses and Their Fair Value [Line Items]
Fair Value	8,358	9,213
Unrealized Losses	124	425
Less Than 12 Months - Fair Value		9,213
Less Than 12 Months - Unrealized Losses		425
12 Months or More - Fair Value	8,358
12 Months or More - Unrealized Losses	124
FNMA [Member]
Note 6 - Debt and Equity Securities (Details) - Available for Sale Securities With Gross Unrealized Losses and Their Fair Value [Line Items]
Fair Value	95,148	139,999
Unrealized Losses	1,717	7,526
Less Than 12 Months - Fair Value		131,248
Less Than 12 Months - Unrealized Losses		6,654
12 Months or More - Fair Value	95,148	8,751
12 Months or More - Unrealized Losses	1,717	872
FHLMC [Member]
Note 6 - Debt and Equity Securities (Details) - Available for Sale Securities With Gross Unrealized Losses and Their Fair Value [Line Items]
Fair Value	6,773	7,478
Unrealized Losses	8	233
Less Than 12 Months - Fair Value	6,773	7,478
Less Than 12 Months - Unrealized Losses	8	233
Collateralized Mortgage Backed Securities [Member]
Note 6 - Debt and Equity Securities (Details) - Available for Sale Securities With Gross Unrealized Losses and Their Fair Value [Line Items]
Fair Value	326,469	454,855
Unrealized Losses	6,476	20,014
Less Than 12 Months - Fair Value	84,155	427,682
Less Than 12 Months - Unrealized Losses	407	17,962
12 Months or More - Fair Value	242,314	27,173
12 Months or More - Unrealized Losses	$ 6,069	$ 2,052

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