Quarterly report pursuant to Section 13 or 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
Mar. 31, 2014
Dec. 31, 2013
Derivatives, Fair Value [Line Items]    
Available-for-sale Securities, Interest-only $ 72,238 $ 75,575
Derivative Financial Instruments, Assets [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Fair Value, Net 429,419 549,859
Derivative, Notional Amount 45,175,522 30,383,908
Derivative Financial Instruments, Liabilities [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Fair Value, Net (8,395) (22,081)
Derivative, Notional Amount 2,894,624 10,876,702
Forward Contracts [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Notional Amount (1,022,000) 603,000
Derivative, Cost (1,086,572) 790,392
Forward Contracts [Member] | Derivative Financial Instruments, Assets [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Fair Value, Net 4,331 33,425
Derivative, Notional Amount 1,100,000 4,097,000
Forward Contracts [Member] | Derivative Financial Instruments, Liabilities [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Fair Value, Net (5,487) (125)
Derivative, Notional Amount 2,372,000 400,000
Options Held [Member] | Derivative Financial Instruments, Assets [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Fair Value, Net 3,627  
Derivative, Notional Amount 1,500,000  
Options Held [Member] | Derivative Financial Instruments, Liabilities [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Fair Value, Net 0  
Derivative, Notional Amount 0  
Forward Purchase Commitment [Member] | Derivative Financial Instruments, Assets [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Fair Value, Net 0 0
Derivative, Notional Amount 0 12,063
Forward Purchase Commitment [Member] | Derivative Financial Instruments, Liabilities [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Fair Value, Net (387) 0
Derivative, Notional Amount 153,637 0
Long [Member]
   
Derivatives, Fair Value [Line Items]    
Agency To-be-Announced Securities, Notional Amount, Mitigate Prepayment Exposure 1,225,000 400,000
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 1,225,000 2,550,000
Derivative, Cost 1,183,028 2,749,648
Long [Member] | Forward Contracts [Member] | Derivative Financial Instruments, Assets [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Fair Value, Net 4,331 17,771
Long [Member] | Forward Contracts [Member] | Derivative Financial Instruments, Liabilities [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Fair Value, Net (493) (125)
Long [Member] | Options Held [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Notional Amount 1,500,000  
Derivative, Cost (5,332)  
Short [Member]
   
Derivatives, Fair Value [Line Items]    
Agency To-be-Announced Securities, Notional Amount, Mitigate Prepayment Exposure 2,247,000 1,947,000
Short [Member] | Forward Contracts [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Notional Amount (2,247,000) (1,947,000)
Derivative, Cost (2,269,600) (1,959,256)
Short [Member] | Forward Contracts [Member] | Derivative Financial Instruments, Assets [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Fair Value, Net 0 15,654
Short [Member] | Forward Contracts [Member] | Derivative Financial Instruments, Liabilities [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Fair Value, Net $ (4,994) $ 0