Schedule III - Real Estate and Accumulated Depreciation - Summary (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Initial cost of encumbrances	$ 2,129,954
Initial cost of land and land improvements	3,760,148
Initial cost of building and improvements	30,524,134
Cost Capitalized Subsequent to Acquisition	6,781,997
Carrying amount of land and land improvements	4,249,834
Carrying amount of building and improvements	36,750,932
Accumulated depreciation	8,075,733	$ 6,910,114	$ 6,104,297	$ 5,715,459
Construction in progress
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Initial cost of encumbrances	22,377
Initial cost of land and land improvements	0
Initial cost of building and improvements	1,021,080
Cost Capitalized Subsequent to Acquisition	0
Carrying amount of land and land improvements	0
Carrying amount of building and improvements	1,021,080
Accumulated depreciation	0
Seniors Housing Operating
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Initial cost of encumbrances	1,679,562
Initial cost of land and land improvements	2,110,584
Initial cost of building and improvements	18,228,152
Cost Capitalized Subsequent to Acquisition	3,775,526
Carrying amount of land and land improvements	2,365,088
Carrying amount of building and improvements	21,749,174
Accumulated depreciation	4,960,254
Seniors Housing Operating | Operating Segments
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Initial cost of encumbrances	1,679,562
Initial cost of land and land improvements	2,110,584
Initial cost of building and improvements	18,228,152
Cost Capitalized Subsequent to Acquisition	3,775,526
Carrying amount of land and land improvements	2,365,088
Carrying amount of building and improvements	21,749,174
Accumulated depreciation	4,960,254
Triple-net
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Initial cost of encumbrances	39,179
Initial cost of land and land improvements	873,139
Initial cost of building and improvements	6,845,480
Cost Capitalized Subsequent to Acquisition	586,644
Carrying amount of land and land improvements	910,570
Carrying amount of building and improvements	7,394,693
Accumulated depreciation	1,549,022
Triple-net | Operating Segments
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Initial cost of encumbrances	39,179
Initial cost of land and land improvements	873,139
Initial cost of building and improvements	6,845,480
Cost Capitalized Subsequent to Acquisition	586,644
Carrying amount of land and land improvements	910,570
Carrying amount of building and improvements	7,394,693
Accumulated depreciation	1,549,022
Outpatient Medical
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Initial cost of encumbrances	388,836
Initial cost of land and land improvements	762,068
Initial cost of building and improvements	4,252,019
Cost Capitalized Subsequent to Acquisition	2,413,016
Carrying amount of land and land improvements	974,176
Carrying amount of building and improvements	6,452,927
Accumulated depreciation	1,566,457
Outpatient Medical | Operating Segments
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Initial cost of encumbrances	388,836
Initial cost of land and land improvements	762,068
Initial cost of building and improvements	4,252,019
Cost Capitalized Subsequent to Acquisition	2,413,016
Carrying amount of land and land improvements	974,176
Carrying amount of building and improvements	6,452,927
Accumulated depreciation	1,566,457
Total continuing operating properties
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Initial cost of encumbrances	2,129,954
Initial cost of land and land improvements	3,745,791
Initial cost of building and improvements	30,346,731
Cost Capitalized Subsequent to Acquisition	6,775,186
Carrying amount of land and land improvements	4,249,834
Carrying amount of building and improvements	36,617,874
Accumulated depreciation	8,075,733
Assets held for sale
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Initial cost of encumbrances	0
Initial cost of land and land improvements	14,357
Initial cost of building and improvements	177,403
Cost Capitalized Subsequent to Acquisition	6,811
Carrying amount of land and land improvements	0
Carrying amount of building and improvements	133,058
Accumulated depreciation	$ 0