Note 6 - Debt and Equity Securities (Details) - Amortized Cost and Fair Value of Securities Available For Sale (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Note 6 - Debt and Equity Securities (Details) - Amortized Cost and Fair Value of Securities Available For Sale [Line Items]
Amortized Cost	$ 967,329	$ 1,032,924
Fair Value	973,310us-gaap_AvailableForSaleSecurities	1,017,790us-gaap_AvailableForSaleSecurities
Gross Unrealized Gains	13,240	13,709
Gross Unrealized Losses	7,259	28,843
Corporate Debt Securities [Member]
Note 6 - Debt and Equity Securities (Details) - Amortized Cost and Fair Value of Securities Available For Sale [Line Items]
Amortized Cost	90,719	100,362
Fair Value	91,273	101,711
Gross Unrealized Gains	1,268	2,316
Gross Unrealized Losses	714	967
Municipal [Member]
Note 6 - Debt and Equity Securities (Details) - Amortized Cost and Fair Value of Securities Available For Sale [Line Items]
Amortized Cost	145,864	127,967
Fair Value	148,896	123,423
Gross Unrealized Gains	3,093	93
Gross Unrealized Losses	61	4,637
Mutual Funds [Member]
Note 6 - Debt and Equity Securities (Details) - Amortized Cost and Fair Value of Securities Available For Sale [Line Items]
Amortized Cost	21,118	21,565
Fair Value	21,118	21,565
Other Debt Obligations [Member]
Note 6 - Debt and Equity Securities (Details) - Amortized Cost and Fair Value of Securities Available For Sale [Line Items]
Amortized Cost	7,098	18,160
Fair Value	7,090	14,935
Gross Unrealized Losses	8	3,225
Available For Sale Securities, Excluding Mortgage-Backed Securities [Member]
Note 6 - Debt and Equity Securities (Details) - Amortized Cost and Fair Value of Securities Available For Sale [Line Items]
Amortized Cost	264,799	268,054
Fair Value	268,377	261,634
Gross Unrealized Gains	4,361	2,409
Gross Unrealized Losses	783	8,829
REMIC And CMO [Member]
Note 6 - Debt and Equity Securities (Details) - Amortized Cost and Fair Value of Securities Available For Sale [Line Items]
Amortized Cost	504,207	494,984
Fair Value	505,768	489,670
Gross Unrealized Gains	6,188	6,516
Gross Unrealized Losses	4,627	11,830
GNMA [Member]
Note 6 - Debt and Equity Securities (Details) - Amortized Cost and Fair Value of Securities Available For Sale [Line Items]
Amortized Cost	13,862	38,974
Fair Value	14,159	40,874
Gross Unrealized Gains	421	2,325
Gross Unrealized Losses	124	425
FNMA [Member]
Note 6 - Debt and Equity Securities (Details) - Amortized Cost and Fair Value of Securities Available For Sale [Line Items]
Amortized Cost	169,956	217,615
Fair Value	170,367	212,322
Gross Unrealized Gains	2,128	2,233
Gross Unrealized Losses	1,717	7,526
FHLMC [Member]
Note 6 - Debt and Equity Securities (Details) - Amortized Cost and Fair Value of Securities Available For Sale [Line Items]
Amortized Cost	14,505	13,297
Fair Value	14,639	13,290
Gross Unrealized Gains	142	226
Gross Unrealized Losses	8	233
Collateralized Mortgage Obligations [Member]
Note 6 - Debt and Equity Securities (Details) - Amortized Cost and Fair Value of Securities Available For Sale [Line Items]
Amortized Cost	702,530	764,870
Fair Value	704,933	756,156
Gross Unrealized Gains	8,879	11,300
Gross Unrealized Losses	$ 6,476	$ 20,014

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Amount of unrealized gain before deducting unrealized loss on investments in debt and equity securities classified as available-for-sale securities.

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Amount of unrealized loss before deducting unrealized gain on investments in available-for-sale securities.

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