Real Estate and Lending Activities - Schedule of Gross Assets by Operator (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Investment And Revenue From External Customers [Line Items]
Total Gross Assets	$ 7,327,837	$ 6,418,536
Total Gross Assets [Member] | Credit Concentration Risk [Member]
Investment And Revenue From External Customers [Line Items]
Total Gross Assets	$ 9,129,778	$ 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	$ 3,410,874	$ 1,250,000
Percentage of Total Gross Assets	37.40%	17.50%
Total Gross Assets [Member] | Credit Concentration Risk [Member] | Prime [Member]
Investment And Revenue From External Customers [Line Items]
Total Gross Assets	$ 1,116,694	$ 1,144,055
Percentage of Total Gross Assets	12.20%	16.00%
Total Gross Assets [Member] | Credit Concentration Risk [Member] | MEDIAN [Member]
Investment And Revenue From External Customers [Line Items]
Total Gross Assets	$ 1,086,109	$ 993,677
Percentage of Total Gross Assets	11.90%	13.90%
Total Gross Assets [Member] | Credit Concentration Risk [Member] | Ernest [Member]
Investment And Revenue From External Customers [Line Items]
Total Gross Assets	$ 630,811	$ 627,906
Percentage of Total Gross Assets	6.90%	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	5.50%	7.90%
Total Gross Assets [Member] | Credit Concentration Risk [Member] | Other Operators [Member]
Investment And Revenue From External Customers [Line Items]
Total Gross Assets	$ 1,977,356	$ 2,259,980
Percentage of Total Gross Assets	21.70%	31.70%
Total Gross Assets [Member] | Credit Concentration Risk [Member] | Other Assets [Member]
Investment And Revenue From External Customers [Line Items]
Total Gross Assets	$ 401,669	$ 300,903
Percentage of Total Gross Assets	4.40%	4.20%