Maturities of Investments in Commercial Mortgages, Mezzanine Loans, Other Loans and Preferred Equity Interests (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Financing Receivables [Line Items]
2014	$ 31,928
2015	90,895
2016	327,416
2017	428,372
2018	57,561
Thereafter	210,402
Total	$ 1,146,574	$ 1,107,583