SEGMENT INFORMATION - Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Assets
Total assets	$ 24,157,840	$ 24,717,786
Percentage of total assets	100.00%	100.00%
Operating Segments | SHOP
Assets
Total assets	$ 12,369,218	$ 12,811,611
Percentage of total assets	51.20%	51.80%
Operating Segments | Office operations
Assets
Total assets	$ 6,558,416	$ 6,341,888
Percentage of total assets	27.10%	25.70%
Operating Segments | Triple-net leased properties
Assets
Total assets	$ 4,272,303	$ 4,578,534
Percentage of total assets	17.70%	18.50%
Non-Segment
Assets
Total assets	$ 957,903	$ 985,753
Percentage of total assets	4.00%	4.00%