Real Estate and Loans Receivable - Concentration of Credit Risks and Related Party Transactions - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Concentration of Credit Risks [Member]
Significant Acquisitions and Disposals [Line Items]
Maximum percentage of entity's total assets invested on single property	4.00%
Concentration of Credit Risks [Member] | California [Member]
Significant Acquisitions and Disposals [Line Items]
Percentage of total assets accounted	24.00%
Percentage of gross assets accounted	18.70%
Concentration of Credit Risks [Member] | Texas[Member]
Significant Acquisitions and Disposals [Line Items]
Percentage of total assets accounted	23.60%
Percentage of gross assets accounted	22.70%
Concentration of Credit Risks [Member] | Minimum [Member] | European
Significant Acquisitions and Disposals [Line Items]
Percentage of total assets accounted	9.00%
Concentration of Credit Risks [Member] | Prime Health Care Services [Member]
Significant Acquisitions and Disposals [Line Items]
Percentage of entity revenue from affiliates	32.00%	27.30%
Percentage of total assets accounted	24.50%	27.90%
Concentration of Credit Risks [Member] | Ernest [Member]
Significant Acquisitions and Disposals [Line Items]
Percentage of entity revenue from affiliates	20.20%	18.60%
Percentage of total assets accounted	15.90%	18.20%
Related Party Transactions [Member]
Significant Acquisitions and Disposals [Line Items]
Lease and interest revenue earned from tenants	$ 70.0	$ 54.3	$ 5.5