Real Property Acquisitions and Development - Construction Activity (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information [Line Items]
Total development projects	$ 28,117	$ 188,344
Expansion projects	0	8,879
Total construction in progress conversions	28,117	197,223
Seniors Housing Operating
Segment Reporting Information [Line Items]
Total development projects	28,117	86,931
Triple-net
Segment Reporting Information [Line Items]
Total development projects	0	90,055
Outpatient Medical
Segment Reporting Information [Line Items]
Total development projects	$ 0	$ 11,358