Real Property Acquisitions and Development - Construction Activity (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Segment Reporting Information [Line Items]
Total development projects	$ 183,701	$ 170,308
Expansion projects	0	35,637
Total construction in progress conversions	183,701	205,945
Seniors Housing Operating
Segment Reporting Information [Line Items]
Total development projects	58,844	93,188
Triple-net
Segment Reporting Information [Line Items]
Total development projects	22,990	33,627
Outpatient Medical
Segment Reporting Information [Line Items]
Total development projects	$ 101,867	$ 43,493