Accounting Policies and Related Matters - Spot Occupancy (Details) - property	Jul. 23, 2021	Jun. 30, 2021	May 31, 2021	Apr. 30, 2021	Mar. 31, 2021	Mar. 12, 2021	Feb. 28, 2021	Jan. 30, 2021	Dec. 31, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Spot occupancy properties									592
COVID-19
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in occupancy basis		2.30%
COVID-19 | United States | Subsequent event
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in occupancy basis	0.60%
COVID-19 | United Kingdom | Subsequent event
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in occupancy basis	0.30%
Seniors Housing Operating | COVID-19
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Spot occupancy		74.60%	73.60%	73.20%	72.60%	72.30%	72.50%	73.30%	74.70%
Sequential occupancy change		0.90%	0.50%	0.50%	0.10%		(0.80%)	(1.40%)
Seniors Housing Operating | COVID-19 | Subsequent event
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in occupancy basis	0.40%