Segment Disclosures - Revenues and Assets by Segment (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Disclosure
Total revenues	$ 431,697	$ 423,565	$ 408,559	$ 381,054	$ 318,920	$ 321,079	$ 307,037	$ 293,303	$ 1,644,875	$ 1,240,339	$ 1,191,320
Total assets	15,920,089				14,032,891				15,920,089	14,032,891
Assets held for sale and discontinued operations, net	2,626,306				3,648,265				2,626,306	3,648,265
Operating segment
Segment Disclosure
Gross assets	14,583,020				11,402,124				14,583,020	11,402,124
Accumulated depreciation and amortization	(2,658,890)				(2,316,724)				(2,658,890)	(2,316,724)
Total assets	11,924,130				9,085,400				11,924,130	9,085,400
Operating segment | Life Science
Segment Disclosure
Total revenues									569,296	440,784	395,064
Gross assets	7,205,949				5,688,659				7,205,949	5,688,659
Operating segment | Medical Office
Segment Disclosure
Total revenues									622,398	621,171	596,399
Gross assets	5,197,777				5,061,351				5,197,777	5,061,351
Operating segment | CCRC
Segment Disclosure
Total revenues									436,494	3,010	0
Gross assets	2,179,294				652,114				2,179,294	652,114
Operating segment | Other Non-reportable
Segment Disclosure
Total revenues									16,687	175,374	$ 199,857
Total assets	584,432				653,746				584,432	653,746
Other non-segment
Segment Disclosure
Total assets	$ 785,221				$ 645,480				$ 785,221	$ 645,480