SEGMENT INFORMATION - Income Statement by Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Revenues
Rental income	$ 1,399,313	$ 1,448,120	$ 1,494,892
Interest and other income	3,635	14,809	7,609
Total revenues	4,129,193	3,828,007	3,795,357
Less:
Interest and other income	3,635	14,809	7,609
Property-level operating expenses	2,276,724	2,084,064	1,937,443
Third party capital management expenses	6,194	4,433	2,315
NOI	1,842,640	1,724,701	1,847,990
Interest expense	(467,557)	(440,089)	(469,541)
Depreciation and amortization	(1,197,798)	(1,197,403)	(1,109,763)
General, administrative and professional fees	(144,874)	(129,758)	(130,158)
Loss on extinguishment of debt, net	(581)	(59,299)	(10,791)
Transaction expenses and deal costs	(51,577)	(47,318)	(29,812)
Allowance on loans receivable and investments	(19,757)	9,082	(24,238)
Other	58,268	37,110	707
Income from unconsolidated entities	28,500	4,983	1,844
Gain on real estate dispositions	7,780	218,788	262,218
Income tax benefit (expense)	16,926	(4,827)	96,534
Income from continuing operations	(40,931)	56,559	441,185
Net (loss) income	(40,931)	56,559	441,185
Other comprehensive (loss) income	6,516	7,551	2,036
Net loss	(47,447)	49,008	439,149
Income from loans and investments	48,160	74,981	80,505
Other	58,268	37,110	707
Income from loans and investments	48,160	74,981	80,505
Resident fees and services
Revenues
Revenue from contracts with customers	2,651,886	2,270,001	2,197,160
Third party capital management revenues
Revenues
Revenue from contracts with customers	26,199	20,096	15,191
Operating Segments | SHOP
Revenues
Rental income	0	0	0
Interest and other income	0	0	0
Total revenues	2,651,886	2,270,001	2,197,160
Less:
Interest and other income	0	0	0
Property-level operating expenses	2,004,420	1,811,728	1,658,671
Third party capital management expenses	0	0	0
NOI	647,466	458,273	538,489
Income from loans and investments	0	0	0
Income from loans and investments	0	0	0
Operating Segments | SHOP | Resident fees and services
Revenues
Revenue from contracts with customers	2,651,886	2,270,001	2,197,160
Operating Segments | SHOP | Third party capital management revenues
Revenues
Revenue from contracts with customers	0	0	0
Operating Segments | Office operations
Revenues
Rental income	801,159	794,297	799,627
Interest and other income	0	0	0
Total revenues	803,607	802,681	808,302
Less:
Interest and other income	0	0	0
Property-level operating expenses	257,003	257,001	256,612
Third party capital management expenses	0	1,798	2,315
NOI	546,604	543,882	549,375
Income from loans and investments	0	0	0
Income from loans and investments	0	0	0
Operating Segments | Office operations | Resident fees and services
Revenues
Revenue from contracts with customers	0	0	0
Operating Segments | Office operations | Third party capital management revenues
Revenues
Revenue from contracts with customers	2,448	8,384	8,675
Operating Segments | Triple-net leased properties
Revenues
Rental income	598,154	653,823	695,265
Interest and other income	0	0	0
Total revenues	598,154	653,823	695,265
Less:
Interest and other income	0	0	0
Property-level operating expenses	15,301	15,335	22,160
Third party capital management expenses	0	0	0
NOI	582,853	638,488	673,105
Income from loans and investments	0	0	0
Income from loans and investments	0	0	0
Operating Segments | Triple-net leased properties | Resident fees and services
Revenues
Revenue from contracts with customers	0	0	0
Operating Segments | Triple-net leased properties | Third party capital management revenues
Revenues
Revenue from contracts with customers	0	0	0
Non-Segment
Revenues
Rental income	0	0	0
Interest and other income	3,635	14,809	7,609
Total revenues	75,546	101,502	94,630
Less:
Interest and other income	3,635	14,809	7,609
Property-level operating expenses	0	0	0
Third party capital management expenses	6,194	2,635	0
NOI	65,717	84,058	87,021
Income from loans and investments	48,160	74,981	80,505
Income from loans and investments	48,160	74,981	80,505
Non-Segment | Resident fees and services
Revenues
Revenue from contracts with customers	0	0	0
Non-Segment | Third party capital management revenues
Revenues
Revenue from contracts with customers	$ 23,751	$ 11,712	$ 6,516