Note 6 - Agency Securities, Available for Sale (Detail) - Summary of Weighted Average Lives of Agency Securities (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Fair Value
Less than one year	$ 2	$ 2,647
Greater than or equal to one year and less than three years	20,289	8,618,862
Greater than or equal to three years and less than five years	3,809,418	9,681,538
Greater than or equal to five years	10,818,469	793,515
Fair value	14,648,178	19,096,562
Amortized Cost
Less than one year	2	2,593
Greater than or equal to one year and less than three years	20,127	8,476,157
Greater than or equal to three years and less than five years	3,837,530	9,592,001
Greater than or equal to five years	10,980,999	795,247
Total Agency Securities	$ 14,838,658	$ 18,865,998