Acquisitions of Real Estate Property - 2020 Acquisitions (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($) property	Dec. 31, 2020 USD ($) property	Dec. 31, 2019 USD ($) property
Business Acquisition [Line Items]
Number of real estate properties	1,200
Payments to acquire real estate | $	$ 1,369,052	$ 78,648	$ 958,125
2020 Acquisitions
Business Acquisition [Line Items]
Payments to acquire real estate | $		$ 249,500
Other 2019 Acquisitions
Business Acquisition [Line Items]
Number of real estate properties			2
Payments to acquire real estate | $			$ 237,000
Office operations | Other 2019 Acquisitions
Business Acquisition [Line Items]
Number of real estate properties			1
Office operations | Research and Innovation Center
Business Acquisition [Line Items]
Number of real estate properties acquired		2
Senior living operations | 2020 Acquisitions
Business Acquisition [Line Items]
Number of real estate properties		7
Senior living operations | Other 2019 Acquisitions
Business Acquisition [Line Items]
Number of real estate properties			2
Triple-net leased properties | LTAC [Member] | 2020 Acquisitions
Business Acquisition [Line Items]
Number of real estate properties		1