Real Estate Activities - Concentration of Credit Risks and Related Party Transactions - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) Investment	Dec. 31, 2017 USD ($) Investment	Dec. 31, 2016 USD ($)
Related Party Transactions [Member]
Business Acquisition [Line Items]
Lease and interest revenue earned from tenants | $	$ 501.4	$ 422.4	$ 282.9
Total Gross Assets [Member] | Geographic Concentration [Member] | U.S. [Member]
Business Acquisition [Line Items]
Percentage of revenue from affiliates of total revenue	80.00%	80.00%
Total Gross Assets [Member] | Geographic Concentration [Member] | Europe [Member]
Business Acquisition [Line Items]
Percentage of revenue from affiliates of total revenue	20.00%	20.00%
Revenue [Member] | Credit Concentration Risk [Member] | Steward [Member]
Business Acquisition [Line Items]
Percentage of revenue from affiliates of total revenue	39.00%	27.00%
Revenue [Member] | Credit Concentration Risk [Member] | Prime [Member]
Business Acquisition [Line Items]
Percentage of revenue from affiliates of total revenue	16.00%	18.00%
Revenue [Member] | Credit Concentration Risk [Member] | MEDIAN [Member]
Business Acquisition [Line Items]
Percentage of revenue from affiliates of total revenue	13.00%	14.00%
Revenue [Member] | Credit Concentration Risk [Member] | Ernest [Member]
Business Acquisition [Line Items]
Percentage of revenue from affiliates of total revenue	8.00%	10.00%
Revenue [Member] | Customer Concentration Risk [Member] | General Acute Care Hospital and Healthcare System [Member]
Business Acquisition [Line Items]
Percentage of revenue from affiliates of total revenue	76.00%	69.00%
Revenue [Member] | Customer Concentration Risk [Member] | Rehabilitation Hospital with Covenant Health System [Member]
Business Acquisition [Line Items]
Percentage of revenue from affiliates of total revenue	20.00%	25.00%
Revenue [Member] | Customer Concentration Risk [Member] | Long-term Acute Care Hospital [Member]
Business Acquisition [Line Items]
Percentage of revenue from affiliates of total revenue	4.00%	6.00%
Pro Forma [Member] | Total Gross Assets [Member] | Customer Concentration Risk [Member]
Business Acquisition [Line Items]
Number of investment in property | Investment	0	0
Maximum percentage of entity's assets invested on single property	4.20%	4.20%