Internal CRE Debt and Preferred Equity Ratings (Detail) (Commercial Mortgage, USD $) In Thousands, unless otherwise specified	Dec. 31, 2013
Transaction to Real Estate Investments [Line Items]
Performing Loans	$ 1,555,750
Internal Ratings Watch List Loans	31,473
Workout Loans
Senior Mortgages
Transaction to Real Estate Investments [Line Items]
Performing Loans	644,039
Internal Ratings Watch List Loans	25,473
Workout Loans
Subordinated Notes
Transaction to Real Estate Investments [Line Items]
Performing Loans	41,059
Workout Loans
Mezzanine Loans
Transaction to Real Estate Investments [Line Items]
Performing Loans	620,883
Internal Ratings Watch List Loans	6,000
Workout Loans
Preferred Equity Interests
Transaction to Real Estate Investments [Line Items]
Performing Loans	249,769
Workout Loans