XML 100 R44.htm IDEA: XBRL DOCUMENT v2.4.0.8
Financial Instruments - Notional and Fair Values of TBAs (Detail) (USD $)
In Thousands, unless otherwise specified
Jun. 30, 2013
Dec. 31, 2012
Fair Value Of To Be Announced Securities [Abstract]    
Notional Amount, Sale of TBAs $ 544,641 $ 449,065
Notional Amount, Purchase of TBAs 100,018 117,573
Notional Amount, Funding Commitments 405,538 304,390
Notional Amount, Total 505,556 421,963
Fair Value, Sale of TBAs 1,750 3,188
Fair Value, Purchase of TBAs $ 1,599 $ 175