SEGMENT INFORMATION - Capital Expenditures (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information
Payments for Capital Improvements	$ 200,557	$ 84,704
Operating Segments | Triple-Net Leased Properties
Segment Reporting Information
Payments for Capital Improvements	7,685	8,591
Operating Segments | Senior Living Operations
Segment Reporting Information
Payments for Capital Improvements	51,884	26,959
Operating Segments | Office Operations
Segment Reporting Information
Payments for Capital Improvements	$ 140,988	$ 49,154