Note 4 - Debt and Equity Securities (Details) - Available for Sale Securities With Gross Unrealized Losses and Their Fair Value (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2015	Dec. 31, 2014
Note 4 - Debt and Equity Securities (Details) - Available for Sale Securities With Gross Unrealized Losses and Their Fair Value [Line Items]
Fair Value	$ 284,363	$ 374,858
Unrealized Losses	3,908	7,259
Less Than 12 Months - Fair Value	118,402	97,274
Less Than 12 Months - Unrealized Losses	1,038	846
12 Months or More - Fair Value	165,961	277,584
12 Months or More - Unrealized Losses	2,870	6,413
Corporate Debt Securities [Member]
Note 4 - Debt and Equity Securities (Details) - Available for Sale Securities With Gross Unrealized Losses and Their Fair Value [Line Items]
Fair Value	49,026	39,287
Unrealized Losses	974	714
Less Than 12 Months - Fair Value	19,389	9,573
Less Than 12 Months - Unrealized Losses	611	428
12 Months or More - Fair Value	29,637	29,714
12 Months or More - Unrealized Losses	363	286
Municipal [Member]
Note 4 - Debt and Equity Securities (Details) - Available for Sale Securities With Gross Unrealized Losses and Their Fair Value [Line Items]
Fair Value	5,268	8,810
Unrealized Losses	33	61
Less Than 12 Months - Fair Value	5,268	3,546
Less Than 12 Months - Unrealized Losses	33	11
12 Months or More - Fair Value		5,264
12 Months or More - Unrealized Losses		50
Other Debt Obligations [Member]
Note 4 - Debt and Equity Securities (Details) - Available for Sale Securities With Gross Unrealized Losses and Their Fair Value [Line Items]
Fair Value	298	292
Unrealized Losses	2	8
12 Months or More - Fair Value	298	292
12 Months or More - Unrealized Losses	2	8
Available For Sale Securities, Excluding Mortgage-Backed Securities [Member]
Note 4 - Debt and Equity Securities (Details) - Available for Sale Securities With Gross Unrealized Losses and Their Fair Value [Line Items]
Fair Value	54,592	48,389
Unrealized Losses	1,009	783
Less Than 12 Months - Fair Value	24,657	13,119
Less Than 12 Months - Unrealized Losses	644	439
12 Months or More - Fair Value	29,935	35,270
12 Months or More - Unrealized Losses	365	344
REMIC And CMO [Member]
Note 4 - Debt and Equity Securities (Details) - Available for Sale Securities With Gross Unrealized Losses and Their Fair Value [Line Items]
Fair Value	158,838	216,190
Unrealized Losses	2,137	4,627
Less Than 12 Months - Fair Value	55,749	77,382
Less Than 12 Months - Unrealized Losses	134	399
12 Months or More - Fair Value	103,089	138,808
12 Months or More - Unrealized Losses	2,003	4,228
GNMA [Member]
Note 4 - Debt and Equity Securities (Details) - Available for Sale Securities With Gross Unrealized Losses and Their Fair Value [Line Items]
Fair Value	8,099	8,358
Unrealized Losses	81	124
Less Than 12 Months - Fair Value	8,099
Less Than 12 Months - Unrealized Losses	81
12 Months or More - Fair Value		8,358
12 Months or More - Unrealized Losses		124
FNMA [Member]
Note 4 - Debt and Equity Securities (Details) - Available for Sale Securities With Gross Unrealized Losses and Their Fair Value [Line Items]
Fair Value	62,834	95,148
Unrealized Losses	681	1,717
Less Than 12 Months - Fair Value	29,897
Less Than 12 Months - Unrealized Losses	179
12 Months or More - Fair Value	32,937	95,148
12 Months or More - Unrealized Losses	502	1,717
Collateralized Mortgage Backed Securities [Member]
Note 4 - Debt and Equity Securities (Details) - Available for Sale Securities With Gross Unrealized Losses and Their Fair Value [Line Items]
Fair Value	229,771	326,469
Unrealized Losses	2,899	6,476
Less Than 12 Months - Fair Value	93,745	84,155
Less Than 12 Months - Unrealized Losses	394	407
12 Months or More - Fair Value	136,026	242,314
12 Months or More - Unrealized Losses	2,505	6,069
FHLMC [Member]
Note 4 - Debt and Equity Securities (Details) - Available for Sale Securities With Gross Unrealized Losses and Their Fair Value [Line Items]
Fair Value		6,773
Unrealized Losses		8
Less Than 12 Months - Fair Value		6,773
Less Than 12 Months - Unrealized Losses		$ 8

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