Real Estate and Other Activities - Concentrations of Credit Risk - Additional Information (Detail)	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Total Gross Assets [Member] | Geographic Concentration [Member] | U.S. [Member]
Business Acquisition [Line Items]
Percentage of concentration risk	63.00%		65.00%
Total Gross Assets [Member] | Geographic Concentration [Member] | Europe [Member]
Business Acquisition [Line Items]
Percentage of concentration risk	31.00%		28.00%
Total Gross Assets [Member] | Geographic Concentration [Member] | Australia [Member]
Business Acquisition [Line Items]
Percentage of concentration risk	5.00%		6.00%
Total Gross Assets [Member] | Geographic Concentration [Member] | South America [Member]
Business Acquisition [Line Items]
Percentage of concentration risk	1.00%		1.00%
Revenue [Member] | Customer Concentration Risk [Member] | General Acute Care Hospital and Healthcare System [Member]
Business Acquisition [Line Items]
Percentage of concentration risk	83.00%	86.00%
Revenue [Member] | Customer Concentration Risk [Member] | Rehabilitation Hospital with Covenant Health System [Member]
Business Acquisition [Line Items]
Percentage of concentration risk	8.00%	9.00%
Revenue [Member] | Customer Concentration Risk [Member] | Long-term Acute Care Hospital [Member]
Business Acquisition [Line Items]
Percentage of concentration risk	2.00%	3.00%
Revenue [Member] | Customer Concentration Risk [Member] | Freestanding ER/Urgent Care Facilities and Behavioral Health Facilities [Member]
Business Acquisition [Line Items]
Percentage of concentration risk	7.00%	2.00%
Revenue [Member] | Credit Concentration Risk [Member] | Steward Health Care System LLC [Member] | Minimum [Member]
Business Acquisition [Line Items]
Percentage of concentration risk	10.00%	10.00%
Revenue [Member] | Credit Concentration Risk [Member] | Prospect [Member] | Minimum [Member]
Business Acquisition [Line Items]
Percentage of concentration risk	10.00%	10.00%
Revenue [Member] | Credit Concentration Risk [Member] | Circle [Member] | Minimum [Member]
Business Acquisition [Line Items]
Percentage of concentration risk	10.00%	10.00%
Pro Forma [Member] | Total Gross Assets [Member] | Customer Concentration Risk [Member]
Business Acquisition [Line Items]
Maximum percentage of entity's assets invested on single property	3.00%		3.00%