Real Estate and Lending Activities - Schedule of Gross Assets by Operator (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Investment And Revenue From External Customers [Line Items]
Total Gross Assets	$ 6,780,730	$ 6,418,536
Total Gross Assets [Member] | Credit Concentration Risk [Member]
Investment And Revenue From External Customers [Line Items]
Total Gross Assets	$ 7,445,822	$ 7,143,121
Percentage of Total Gross Assets	100.00%	100.00%
Total Gross Assets [Member] | Credit Concentration Risk [Member] | Steward [Member]
Investment And Revenue From External Customers [Line Items]
Total Gross Assets	$ 1,551,292	$ 1,250,000
Percentage of Total Gross Assets	20.80%	17.50%
Total Gross Assets [Member] | Credit Concentration Risk [Member] | Prime [Member]
Investment And Revenue From External Customers [Line Items]
Total Gross Assets	$ 1,115,356	$ 1,144,055
Percentage of Total Gross Assets	15.00%	16.00%
Total Gross Assets [Member] | Credit Concentration Risk [Member] | MEDIAN [Member]
Investment And Revenue From External Customers [Line Items]
Total Gross Assets	$ 1,006,432	$ 993,677
Percentage of Total Gross Assets	13.50%	13.90%
Total Gross Assets [Member] | Credit Concentration Risk [Member] | Ernest [Member]
Investment And Revenue From External Customers [Line Items]
Total Gross Assets	$ 627,971	$ 627,906
Percentage of Total Gross Assets	8.40%	8.80%
Total Gross Assets [Member] | Credit Concentration Risk [Member] | RCCH [Member]
Investment And Revenue From External Customers [Line Items]
Total Gross Assets	$ 506,265	$ 566,600
Percentage of Total Gross Assets	6.80%	7.90%
Total Gross Assets [Member] | Credit Concentration Risk [Member] | Other Operators [Member]
Investment And Revenue From External Customers [Line Items]
Total Gross Assets	$ 2,313,871	$ 2,259,980
Percentage of Total Gross Assets	31.10%	31.70%
Total Gross Assets [Member] | Credit Concentration Risk [Member] | Other Assets [Member]
Investment And Revenue From External Customers [Line Items]
Total Gross Assets	$ 324,635	$ 300,903
Percentage of Total Gross Assets	4.40%	4.20%