Annual report pursuant to Section 13 and 15(d)

Derivative Instruments and Hedging Activities Interest Rate Sensitive Assets/Liabilities (Details)

v2.4.0.8
Derivative Instruments and Hedging Activities Interest Rate Sensitive Assets/Liabilities (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2013
Dec. 31, 2012
Derivatives, Fair Value [Line Items]    
Available-for-sale Securities, Interest-only $ 75,575 $ 77,342
Derivative Financial Instruments, Assets [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Notional Amount 30,383,908 9,768,656
Derivative, Fair Value, Net 549,859 462,080
Forward Contracts [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Notional Amount 603,000 953,000
Derivative, Cost 790,392 1,009,996
Forward Contracts [Member] | Derivative Financial Instruments, Assets [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Notional Amount 4,097,000 2,414,000
Derivative, Fair Value, Net 33,425 1,917
Forward Purchase Commitment [Member] | Derivative Financial Instruments, Assets [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Notional Amount 12,063 56,865
Derivative, Fair Value, Net 0 234
Long [Member]
   
Derivatives, Fair Value [Line Items]    
Agency To-be-Announced Securities, Notional Amount, Mitigate Prepayment Exposure 400,000 1,753,000
Long [Member] | Forward Contracts [Member]
   
Derivatives, Fair Value [Line Items]    
Agency To-be-Announced Securities, Notional Amount, Non-Risk Management 2,150,000  
Derivative, Notional Amount 2,550,000 1,753,000
Derivative, Cost 2,749,648 1,867,621
Long [Member] | Forward Contracts [Member] | Derivative Financial Instruments, Assets [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Fair Value, Net 17,771 1,729
Short [Member]
   
Derivatives, Fair Value [Line Items]    
Agency To-be-Announced Securities, Notional Amount, Mitigate Prepayment Exposure 1,947,000 800,000
Short [Member] | Forward Contracts [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Notional Amount 1,947,000 800,000
Derivative, Cost (1,959,256) (857,625)
Short [Member] | Forward Contracts [Member] | Derivative Financial Instruments, Assets [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Fair Value, Net $ 15,654 $ 188