Summary of Total Recourse and Non-Recourse Indebtedness (Parenthetical) (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Principal amount of senior secured notes issued	$ 90,000	$ 94,000
Carrying Amount	1,919,620	1,799,595
Principal amount of investment in securities and security-related receivables and loans	1,035,821	1,118,346
Fair value of investments securitized	791,642	849,919
Cbms Facility
Debt Instrument [Line Items]
Carrying Amount		1,757,789
7.0% convertible senior notes
Debt Instrument [Line Items]
Stated interest rate	7.00%	7.00%
CMBS Facilities
Debt Instrument [Line Items]
Carrying Amount	$ 1,760,167