SEGMENT INFORMATION - Capital Expenditures (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Information
Payments for Capital Improvements	$ 1,221,944	$ 170,613	$ 1,427,170	$ 481,999
Operating Segments | Triple-Net Leased Properties
Segment Reporting Information
Payments for Capital Improvements	75,544	11,832	92,683	33,000
Operating Segments | Senior Living Operations
Segment Reporting Information
Payments for Capital Improvements	1,093,773	46,349	1,193,646	129,165
Operating Segments | Office Operations
Segment Reporting Information
Payments for Capital Improvements	$ 52,627	$ 112,432	$ 140,841	$ 319,834