Real Estate and Lending Activities - Concentrations of Credit Risk - Additional Information (Detail) (Concentration of Credit Risks [Member])	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Significant Acquisitions and Disposals [Line Items]
Maximum percentage of entity's total assets invested on single property	4.00%
California [Member]
Significant Acquisitions and Disposals [Line Items]
Percentage of total assets accounted	17.90%		18.70%
Texas [Member]
Significant Acquisitions and Disposals [Line Items]
Percentage of total assets accounted	22.00%		22.70%
European [Member] | Minimum [Member]
Significant Acquisitions and Disposals [Line Items]
Percentage of total assets accounted	8.00%
Ernest [Member]
Significant Acquisitions and Disposals [Line Items]
Percentage of entity revenue from affiliates	19.50%	20.50%
Percentage of total assets accounted	15.80%		15.90%
Prime Health Care Services [Member]
Significant Acquisitions and Disposals [Line Items]
Percentage of entity revenue from affiliates	29.10%	31.40%
Percentage of total assets accounted	23.50%		24.50%