Loans Receivable - Types of Loans in Loan Portfolio, as well as Property Type and Geographic Distribution of Properties Securing these Loans (Parenthetical) (Detail) (Senior Mortgages Loans [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2013
Senior Mortgages Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Contiguous subordinated loans	$ 68.6