XML 43 R87.htm IDEA: XBRL DOCUMENT v2.4.0.6
Derivative Financial Instruments-Balance Sheet Information (Detail) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2012
Dec. 31, 2011
Derivative Instruments, Gain (Loss) [Line Items]    
Derivative Financial Instruments Not Designated as Hedging Instruments, Unrealized Gain / (Loss) $ 22 $ (16)
Investments-trading [Member] | TBAs [Member]
   
Derivative Instruments, Gain (Loss) [Line Items]    
Derivative Financial Instruments Not Designated as Hedging Instruments, Unrealized Gain / (Loss) 35  
Trading securities sold not yet purchased [Member] | TBAs [Member]
   
Derivative Instruments, Gain (Loss) [Line Items]    
Derivative Financial Instruments Not Designated as Hedging Instruments, Unrealized Gain / (Loss) $ (13) $ (16)