Annual report pursuant to Section 13 and 15(d)

Repurchase Agreements Schedule of Underlying Assets of Repurchase Agreements when Amount of Repurchase Agreements Exceeds 10 Percent of Assets (Details)

v2.4.0.6
Repurchase Agreements Schedule of Underlying Assets of Repurchase Agreements when Amount of Repurchase Agreements Exceeds 10 Percent of Assets (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2011
Dec. 31, 2010
Assets Sold under Agreements to Repurchase [Line Items]    
Assets Sold under Agreements to Repurchase, Market Value $ 7,457,095 $ 1,357,264
Available-for-sale Securities [Member]
    
Assets Sold under Agreements to Repurchase [Line Items]    
Assets Sold under Agreements to Repurchase, Market Value 6,160,229 1,090,598
US Treasury Securities [Member]
    
Assets Sold under Agreements to Repurchase [Line Items]    
Assets Sold under Agreements to Repurchase, Market Value 1,003,301 199,523
Loans Held-for-sale, Mortgages [Member]
    
Assets Sold under Agreements to Repurchase [Line Items]    
Assets Sold under Agreements to Repurchase, Market Value 5,782 0
Cash and Cash Equivalents [Member]
    
Assets Sold under Agreements to Repurchase [Line Items]    
Assets Sold under Agreements to Repurchase, Market Value 15,000 14,467
Restricted Cash and Cash Equivalents [Member]
    
Assets Sold under Agreements to Repurchase [Line Items]    
Assets Sold under Agreements to Repurchase, Market Value 94,803 11,634
Due From Correspondent Brokers [Member]
    
Assets Sold under Agreements to Repurchase [Line Items]    
Assets Sold under Agreements to Repurchase, Market Value 32,201 10,508
Derivative Financial Instruments, Assets [Member]
    
Assets Sold under Agreements to Repurchase [Line Items]    
Assets Sold under Agreements to Repurchase, Market Value $ 145,779 $ 30,534