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
Jun. 30, 2013
Dec. 31, 2012
Derivatives, Fair Value [Line Items]    
Available-for-sale Securities, Interest-only $ 95,039 $ 77,342
Derivative Financial Instruments, Assets [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Fair Value, Net 699,351 462,080
Derivative, Notional Amount 29,556,972 9,768,656
Derivative Financial Instruments, Liabilities [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Fair Value, Net (46,028) (129,294)
Derivative, Notional Amount 23,551,633 14,209,000
Forward Contracts [Member] | Derivative Financial Instruments, Assets [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Fair Value, Net 61,156 1,917
Derivative, Notional Amount 2,813,000 2,414,000
Forward Contracts [Member] | Derivative Financial Instruments, Liabilities [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Fair Value, Net (22,568) (239)
Derivative, Notional Amount 2,892,000 139,000
Options Held [Member] | Derivative Financial Instruments, Assets [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Fair Value, Net 24,873  
Derivative, Notional Amount 210,000  
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 0 234
Derivative, Notional Amount 0 56,865
Forward Purchase Commitment [Member] | Derivative Financial Instruments, Liabilities [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Fair Value, Net (1,204) 0
Derivative, Notional Amount 29,229 0
Long [Member]
   
Derivatives, Fair Value [Line Items]    
Agency To-be-Announced Securities, Notional Amount, Mitigate Prepayment Exposure 92,000  
Long [Member] | Forward Contracts [Member]
   
Derivatives, Fair Value [Line Items]    
Agency To-be-Announced Securities, Notional Amount, Non-Risk Management 1,400,000  
Derivative, Notional Amount 1,492,000 1,753,000
Long [Member] | Options Held [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Notional Amount 1,315,000  
Derivative, Cost (9,992)  
Short [Member]
   
Derivatives, Fair Value [Line Items]    
Agency To-be-Announced Securities, Notional Amount, Mitigate Prepayment Exposure 4,213,000  
Short [Member] | Forward Contracts [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Notional Amount 4,213,000 800,000
Short [Member] | Options Held [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative, Notional Amount (1,525,000)  
Derivative, Cost $ 8,348