v2.4.0.6
Realized and Net Change in Unrealized Gains (Losses) on Financial Instruments on Financial Instruments on Which Fair Value Option was Elected (Detail) (USD $)
In Thousands, unless otherwise specified
 3 Months Ended 6 Months Ended
Jun. 30, 2012
Jun. 30, 2011
Jun. 30, 2012
Jun. 30, 2011
Realized Gains (Losses) | Assets
        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Realized and net change in unrealized gains (losses) on financial instruments $ (62,262) $ 22,982 $ (22,461) $ 67,741
Realized Gains (Losses) | Liabilities
        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Realized and net change in unrealized gains (losses) on financial instruments 1 (2,319) (43) (7,714)
Realized Gains (Losses) | Corporate Loans
        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Realized and net change in unrealized gains (losses) on financial instruments (63,992) 22,880 (24,718) 65,112
Realized Gains (Losses) | Corporate Bonds
        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Realized and net change in unrealized gains (losses) on financial instruments 311 102 718 2,149
Realized Gains (Losses) | Other
        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Realized and net change in unrealized gains (losses) on financial instruments 1,419   1,539 480
Realized Gains (Losses) | Senior Secured Notes
        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Realized and net change in unrealized gains (losses) on financial instruments 1 (2,319) (43) (7,714)
Net Change In Unrealized Gains (Losses) | Assets
        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Realized and net change in unrealized gains (losses) on financial instruments 15,319 (86,767) 320,718 (31,202)
Net Change In Unrealized Gains (Losses) | Liabilities
        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Realized and net change in unrealized gains (losses) on financial instruments 20,738 (136,166) (106,948) (400,181)
Net Change In Unrealized Gains (Losses) | Loans And Receivables
        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Realized and net change in unrealized gains (losses) on financial instruments (402) (287) (396) (287)
Net Change In Unrealized Gains (Losses) | Corporate Loans
        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Realized and net change in unrealized gains (losses) on financial instruments 12,481 (83,940) 301,712 (33,721)
Net Change In Unrealized Gains (Losses) | Corporate Bonds
        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Realized and net change in unrealized gains (losses) on financial instruments (3,386) (1,293) 9,295 (1,322)
Net Change In Unrealized Gains (Losses) | Other
        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Realized and net change in unrealized gains (losses) on financial instruments 6,626 (1,247) 10,107 4,128
Net Change In Unrealized Gains (Losses) | Senior Secured Notes
        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Realized and net change in unrealized gains (losses) on financial instruments (21,509) (92,519) (114,712) (332,477)
Net Change In Unrealized Gains (Losses) | Subordinated Notes
        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Realized and net change in unrealized gains (losses) on financial instruments $ 42,247 $ (43,647) $ 7,764 $ (67,704)