Dispositions of Real Estate and Discontinued Operations - Held for Sale and Discontinued Operations (Details) - property	1 Months Ended	3 Months Ended		12 Months Ended
	Jan. 31, 2021	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Senior housing triple-net
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of assets to be sold			18
Medical office
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of assets to be sold				11
SHOP
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of assets to be sold	16	1	7	23
Held-for-sale | Senior housing triple-net
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties classified as held for sale		9		41
Held-for-sale | Medical office
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties classified as held for sale		8		6
Held-for-sale | SHOP
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties classified as held for sale		48		97
Held-for-sale | Senior Housing Operating Portfolio Joint Venture
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties classified as held for sale		1		1