Investments in and Advances to Unconsolidated Joint Ventures (Details) $ in Thousands	1 Months Ended			3 Months Ended		9 Months Ended		12 Months Ended
	May 31, 2021 USD ($) property	Apr. 30, 2021 USD ($) property	Jan. 31, 2021 property	Sep. 30, 2021 USD ($) joint_venture property	Sep. 30, 2020 USD ($) property	Sep. 30, 2021 USD ($) property joint_venture	Sep. 30, 2020 USD ($) property	Dec. 31, 2020 USD ($) property joint_venture	Jan. 31, 2020 property
Schedule of Equity Method Investments [Line Items]
Property count									15
Investments in and advances to unconsolidated joint ventures | $				$ 389,095		$ 389,095		$ 402,871
Discovery Naples JV
Schedule of Equity Method Investments [Line Items]
Investment ownership percentage								41.00%
Discovery Sarasota JV
Schedule of Equity Method Investments [Line Items]
Investment ownership percentage								47.00%
SWF SH JV
Schedule of Equity Method Investments [Line Items]
Property count				19		19
Investment ownership percentage				54.00%		54.00%
Equity method investments | $				$ 354,534		$ 354,534		$ 357,581
Life science joint ventures
Schedule of Equity Method Investments [Line Items]
Property count				1		1
Investment ownership percentage				49.00%		49.00%
Equity method investments | $				$ 25,135		$ 25,135		24,879
Medical Office JVs
Schedule of Equity Method Investments [Line Items]
Property count				3		3
Equity method investments | $				$ 9,426		$ 9,426		9,673
Number of unconsolidated joint ventures (in joint ventures) | joint_venture				3		3
Medical Office JVs | Minimum
Schedule of Equity Method Investments [Line Items]
Investment ownership percentage				20.00%		20.00%
Medical Office JVs | Maximum
Schedule of Equity Method Investments [Line Items]
Investment ownership percentage				67.00%		67.00%
HCP Ventures IV, LLC
Schedule of Equity Method Investments [Line Items]
Investment ownership percentage				20.00%		20.00%
HCP Ventures III, LLC
Schedule of Equity Method Investments [Line Items]
Investment ownership percentage				30.00%		30.00%
Suburban Properties, LLC
Schedule of Equity Method Investments [Line Items]
Investment ownership percentage				67.00%		67.00%
Other JVs
Schedule of Equity Method Investments [Line Items]
Property count				0		0
Equity method investments | $				$ 0		$ 0		$ 9,157
CCRC JV
Schedule of Equity Method Investments [Line Items]
Property count				0		0
Investment ownership percentage	49.00%							49.00%	49.00%
Equity method investments | $				$ 0		$ 0		$ 1,581
Proceeds from sale of buildings | $	$ 19,000
Otay Ranch
Schedule of Equity Method Investments [Line Items]
Proceeds from sale of equity method investments | $		$ 32,000
Otay Ranch | Discontinued Operations
Schedule of Equity Method Investments [Line Items]
Gain on sale of unconsolidated joint venture | $		$ 5,000
Otay Ranch | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Investment ownership percentage								90.00%
Equity method investments | $								$ 6,000
Discovery Naples JV and Discovery Sarasota JV
Schedule of Equity Method Investments [Line Items]
Number of unconsolidated joint ventures (in joint ventures) | joint_venture								2
Brookedale MTCA | CCRC JV
Schedule of Equity Method Investments [Line Items]
Number of assets to be sold	2
Proceeds from sale of buildings | $	$ 38,000
Other non-reportable
Schedule of Equity Method Investments [Line Items]
Number of assets to be sold					1		1	1
Proceeds from sale of buildings | $					$ 1,000		$ 1,000	$ 1,000
Other non-reportable | Lessor Asset Under Operating Lease
Schedule of Equity Method Investments [Line Items]
Property count								1
Other non-reportable | Brookedale MTCA | Lessor Asset Under Operating Lease
Schedule of Equity Method Investments [Line Items]
Property count									13
SHOP
Schedule of Equity Method Investments [Line Items]
Number of assets to be sold			16	8	4	15	13	23
SHOP | Discovery SHOP Portfolio
Schedule of Equity Method Investments [Line Items]
Number of assets to be sold		10
Number of preferred equity method investments sold		2