Segment Disclosures - Revenues by Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Disclosure
Total revenues	$ 588,440	$ 491,567	$ 1,173,590	$ 927,721
Operating segment
Segment Disclosure
Total revenues	588,440	491,567	1,173,590	927,721
Operating segment | Senior housing triple-net
Segment Disclosure
Total revenues	24,589	49,805	57,724	108,637
Operating segment | SHOP
Segment Disclosure
Total revenues	155,293	177,001	326,254	303,182
Operating segment | CCRC
Segment Disclosure
Total revenues	113,926	0	205,706	0
Operating segment | Life science
Segment Disclosure
Total revenues	138,496	107,596	267,379	202,068
Operating segment | Medical office
Segment Disclosure
Total revenues	141,636	141,927	286,782	284,122
Operating segment | Other Non-reportable
Segment Disclosure
Total revenues	$ 14,500	$ 15,238	$ 29,745	$ 29,712