v2.4.0.6
Significant Accounting Policies (Details) (USD $)
 9 Months Ended 12 Months Ended 9 Months Ended 12 Months Ended 9 Months Ended 12 Months Ended 9 Months Ended 12 Months Ended 9 Months Ended 1 Months Ended
Sep. 30, 2012
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Dec. 31, 2011
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Sep. 30, 2012
Maximum [Member]
Dec. 31, 2011
Maximum [Member]
Sep. 30, 2012
Minimum [Member]
Dec. 31, 2011
Minimum [Member]
Sep. 30, 2012
Weighted Average [Member]
Dec. 31, 2011
Weighted Average [Member]
Sep. 30, 2012
TBA - Fixed Rate Agency Securities [Member]
Dec. 31, 2011
TBA - Fixed Rate Agency Securities [Member]
Sep. 30, 2012
TBA - Fixed Rate Agency Securities Sold Short [Member]
Dec. 31, 2011
TBA - Fixed Rate Agency Securities Sold Short [Member]
Sep. 30, 2012
Total Return Swaps [Member]
Dec. 31, 2011
Total Return Swaps [Member]
Sep. 30, 2012
Interest Rate Swaps [Member]
Dec. 31, 2011
Interest Rate Swaps [Member]
Sep. 30, 2012
Credit Default Swaps [Member]
Dec. 31, 2011
Credit Default Swaps [Member]
Sep. 30, 2012
Futures [Member]
Dec. 31, 2011
Futures [Member]
Sep. 30, 2012
Long-Term Incentive Plan Units [Member]
Non-Manager [Member]
Aug. 31, 2010
Long-Term Incentive Plan Units [Member]
Non-Employees [Member]
Significant Accounting Policies [Line Items]                                            
Percentage of average monthly notional amount                         100.00% 354.00% 110.00% 111.00% 90.00% 92.00% 69.00% 65.00%    
Reverse repurchase agreements remaining terms, days     180 days 180 days 2 days 3 days 68 days 33 days                            
Reverse repurchase agreements interest rate     2.80% 2.56% 0.31% 0.08% 1.07% 0.82%                            
Investments, Fair Value $ 1,165,644,000 $ 1,212,483,000             $ 33,723,000 [1],[2],[3] $ 32,033,000 [1],[4],[5]                        
Percentage of open reserve repurchase agreements 64.00% 73.00%                                        
Fair value of asset subject to resecuritization 2,400,000                                          
Number of counterparties 3 4                                        
Receivable for securities sold 494,842,000 533,708,000             441,800,000 443,700,000                        
Fair value 456,824,000 462,394,000                 443,191,000 [1],[6] 446,707,000 [1],[7]                    
Payable for securities purchased 178,453,000 127,517,000                 33,700,000 32,500,000                    
Net short position, TBA                     $ 409,500,000 $ 414,700,000                    
LTIP vesting period (years)                                           3 years
Vesting period (years)                                         1 year  
[1] See Note 2 and Note 3 in Notes to Consolidated Financial Statements.
[2] At September 30, 2012, the Company's long investments guaranteed by the Federal National Mortgage Association, the Federal Home Loan Mortgage Corporation, and the Government National Mortgage Association represented 104.58%, 25.88%, and 0.67% of shareholders' equity, respectively.
[3] The table below shows the Company's long investment ratings from Moody's, Standard and Poor's, or Fitch, as well as the Company's long investments that were unrated but affiliated with Fannie Mae, Freddie Mac, or Ginnie Mae. Ratings tend to be a lagging credit indicator; as a result, the credit quality of the Company's long investment holdings may be lower than the credit quality implied based on the ratings listed below. In situations where an investment has a split rating, the lowest provided rating is used. The ratings descriptions include ratings qualified with a "+", "-", "1", "2", or "3". Percentage of Shareholders' Rating Description Equity Unrated but Agency-Guaranteed 131.13 % Aaa/AAA/AAA 0.02 % Aa/AA/AA 0.45 % A/A/A 1.85 % Baa/BBB/BBB 8.25 % Ba/BB/BB or below 90.44 % Unrated 1.62 %
[4] At December 31, 2011, the Company's long investments guaranteed by the Federal National Mortgage Association, the Federal Home Loan Mortgage Corporation, and the Government National Mortgage Association represented 142.04%, 63.62%, and 0.41% of shareholders' equity, respectively.
[5] The table below shows the Company's long investment ratings from Moody's, Standard and Poor's, or Fitch, as well as the Company's long investments that were unrated but affiliated with Fannie Mae, Freddie Mac, or Ginnie Mae. Ratings tend to be a lagging credit indicator; as a result, the credit quality of the Company's long investment holdings may be lower than the credit quality implied based on the ratings listed below. In situations where an investment has a split rating, the lowest provided rating is used. The ratings descriptions include ratings qualified with a "+," "-," "1," "2" or "3." Percentage of Rating Description Shareholders' Equity U.S. Treasury Securities 2.72 % Unrated but Agency-Guaranteed 206.07 % Aaa/AAA/AAA 1.25 % Aa/AA/AA 1.88 % A/A/A 5.44 % Baa/BBB/BBB 3.46 % Ba/BB/BB or below 103.36 % Unrated 2.71 %
[6] At September 30, 2012, the Company's short investments guaranteed by the Federal National Mortgage Association and the Federal Home Loan Mortgage Corporation represented 75.14% and 13.74% of shareholders' equity, respectively.
[7] At December 31, 2011, the Company's short investments guaranteed by the Federal National Mortgage Association, the Federal Home Loan Mortgage Corporation, and the Government National Mortgage Association represented 93.03%, 19.18%, and 8.22% of shareholders' equity, respectively.