Fair Value of Financial Instruments - Summary of Fair Value Information of Financial Instruments (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013		Dec. 31, 2012
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest and rent receivables	$ 54,505		$ 45,289
Loans	331,612	[1]	334,693	[1]
Debt, net	(1,086,973)		(1,025,160)
Estimate of Fair Value, Fair Value Disclosure
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest and rent receivables	43,723		36,700
Loans	329,367	[1]	335,595	[1]
Debt, net	$ (1,116,389)		$ (1,082,333)

[1] Excludes loans related to the Ernest Transaction since they are recorded at fair value and discussed below.