Loans Receivable - Overall Statistics for Loans Receivable Portfolio (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013 Investment	Dec. 31, 2012 Investment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net book value	$ 2,047,223	$ 141,500
Weighted-average cash coupon	L+2.23 %
Loans Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans	31	7
Principal Balance	2,076,411	164,180
Net book value	$ 2,047,223	$ 141,500
Weighted-average cash coupon	L+4.64 %	L+4.73 %
Weighted-average all-in yield	L+5.26 %	L+4.74 %
Weighted-average maximum maturity (years)	4 years 1 month 6 days	8 months 12 days