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
 12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 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 $ 41,831 $ (33,271) $ 90,709
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 (6,078) 17 10,492
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 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 (2,833) (353)  
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 37,464 (35,428) 76,314
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 4,510 393 1,099
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 2,647 2,425 13,296
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 (6,078) 17 5,798
Realized 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     4,694
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 173,606 579,906 (374,871)
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 (388,664) (672,391) 102,128
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 (1,101) (375) (228)
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 7,273 500  
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 172,968 554,628 (396,946)
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 (5,058) 13,264 (7,605)
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 (476) 11,889 29,908
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 (485,655) (603,250) 58,067
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 $ 96,991 $ (69,141) $ 44,061