Note 5 - Agency Securities, Available for Sale (Detail) - Summary of Weighted Average Lives of Agency Securities (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Greater than three years and less than five years	$ 95,921	$ 638,744
Greater than three years and less than five years	96,844	641,231
Greater than or equal to five years	982,360	473,614
Greater than or equal to five years	1,001,879	475,729
Total Agency Securities	1,078,281	1,112,358
Total Agency Securities	$ 1,098,723	$ 1,116,960

Amount of available-for-sale debt securities at cost, net of adjustments, which include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings (less any cumulative-effect adjustments, as defined) and fair value hedge accounting adjustments.

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Amount of debt securities categorized neither as held-to-maturity nor trading.

+ References

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