Real Estate and Loans Receivable - Intangible Assets - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Significant Acquisitions and Disposals [Line Items]
Intangible lease assets	$ 108,885,000	$ 90,490,000
Intangible Assets [Member]
Significant Acquisitions and Disposals [Line Items]
Intangible lease assets	108,900,000	90,500,000
Accumulated amortization, net	87,700,000	74,900,000
Amortization expense related to intangible lease assets	$ 7,000,000	$ 4,000,000	$ 3,900,000
Capitalized lease intangibles, weighted average life (in years)	17 years 10 months 24 days