v2.4.0.8
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 9 Months Ended
Sep. 30, 2013
Sep. 30, 2012
Sep. 30, 2013
Sep. 30, 2012
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 $ (14,719) $ (2,212) $ 32,079 $ (24,673)
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 (2,833) 60 (2,833) 17
Realized 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   (308) 43 (308)
Realized Gains (Losses) | Equity and Preferred Securities
        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Realized and net change in unrealized gains (losses) on financial instruments (622)   (2,020)  
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 (14,533) (2,522) 28,541 (27,240)
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 156 (268) 3,809 450
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 280 886 1,706 2,425
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 (2,833) 60 (2,833) 17
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 87,908 165,510 118,111 486,228
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 (108,706) (393,825) (322,650) (374,518)
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 (897) 30 (1,101) (366)
Net Change In Unrealized Gains (Losses) | Equity and Preferred Securities
        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Realized and net change in unrealized gains (losses) on financial instruments 1,206   1,487  
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 90,412 163,390 125,284 465,102
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 1,262 708 (4,596) 10,003
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 (4,075) 1,382 (2,963) 11,489
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 (127,864) (289,500) (419,817) (335,598)
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 $ 19,158 $ (104,325) $ 97,167 $ (38,920)