Segment Disclosures - Revenues by Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Disclosure
Total revenues	$ 585,150	$ 436,154
Operating segment
Segment Disclosure
Total revenues	585,150	436,154
Operating segment | Senior housing triple-net
Segment Disclosure
Total revenues	33,135	58,831
Operating segment | SHOP
Segment Disclosure
Total revenues	170,961	126,181
Operating segment | CCRC
Segment Disclosure
Total revenues	91,780	0
Operating segment | Life science
Segment Disclosure
Total revenues	128,883	94,473
Operating segment | Medical office
Segment Disclosure
Total revenues	145,146	142,195
Operating segment | Other non-reportable segments
Segment Disclosure
Total revenues	$ 15,245	$ 14,474