Fair Values - Schedule of Range of Key Assumptions for Each Type of Loans Receivable (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Hotel [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Discount Rate	7.00%	7.00%
Fair Value of a 100 bp discount rate increase	0.30%	1.40%
Office [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Fair Value of a 100 bp discount rate increase	1.10%	0.30%
Minimum [Member] | Office [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Discount Rate		6.00%
Maximum [Member] | Office [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Discount Rate	15.00%	15.00%