Real Estate and Lending Activities - Concentrations of Credit Risk - Additional Information (Detail) (Concentration of Credit Risks [Member])	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Significant Acquisitions and Disposals [Line Items]
Number of investment in property	0		0
Maximum percentage of entity's total assets invested on single property	4.00%		4.00%
California [Member]
Significant Acquisitions and Disposals [Line Items]
Percentage of total assets accounted			17.20%		18.70%
Texas [Member]
Significant Acquisitions and Disposals [Line Items]
Percentage of total assets accounted			22.50%		22.70%
European [Member] | Minimum [Member]
Significant Acquisitions and Disposals [Line Items]
Percentage of total assets accounted			9.00%
Ernest [Member]
Significant Acquisitions and Disposals [Line Items]
Percentage of entity revenue from affiliates	26.40%	33.90%	27.80%	32.60%
Percentage of total assets accounted	22.50%				24.50%
Prime Health Care Services [Member]
Significant Acquisitions and Disposals [Line Items]
Percentage of entity revenue from affiliates	18.30%	20.80%	18.70%	20.60%
Percentage of total assets accounted	15.30%				15.90%