SEGMENT INFORMATION - Income Statement by Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenues
Rental income	$ 1,486,401	$ 1,399,313	$ 1,448,120
Interest and other income	11,414	3,635	14,809
Total revenues	4,497,827	4,129,193	3,828,007
Less:
Interest and other income	11,414	3,635	14,809
Property-level operating expenses	2,555,145	2,276,724	2,084,064
Third party capital management expenses	6,101	6,194	4,433
NOI	1,925,167	1,842,640	1,724,701
Interest expense	(574,112)	(467,557)	(440,089)
Depreciation and amortization	(1,392,461)	(1,197,798)	(1,197,403)
General, administrative and professional fees	(148,876)	(144,874)	(129,758)
Loss on extinguishment of debt, net	6,104	(581)	(59,299)
Transaction, transition and restructuring costs	(15,215)	(30,884)	(47,318)
Allowance on loans receivable and investments	20,270	(19,757)	9,082
Shareholder relations matters	0	(20,693)	0
Other (income) expense	(23,001)	58,268	37,110
Income from unconsolidated entities	13,626	28,500	4,983
Gain on real estate dispositions	62,119	7,780	218,788
Income tax benefit (expense)	9,539	16,926	(4,827)
Net (loss) income	(30,297)	(40,931)	56,559
Other comprehensive income (loss)	10,676	6,516	7,551
Net loss	(40,973)	(47,447)	49,008
Income from loans and investments	22,952	48,160	74,981
(Loss) income from continuing operations	(30,297)	(40,931)	56,559
Gain on foreclosure of real estate	29,127	0	0
Other (income) expense	(23,001)	58,268	37,110
Income from loans and investments	22,952	48,160	74,981
(Loss) income from continuing operations	(30,297)	(40,931)	56,559
Resident fees and services
Revenues
Revenue from contracts with customers	2,959,219	2,651,886	2,270,001
Third party capital management revenues
Revenues
Revenue from contracts with customers	17,841	26,199	20,096
Operating Segments | SHOP
Revenues
Rental income	0	0	0
Interest and other income	0	0	0
Total revenues	2,959,219	2,651,886	2,270,001
Less:
Interest and other income	0	0	0
Property-level operating expenses	2,247,812	2,004,420	1,811,728
Third party capital management expenses	0	0	0
NOI	711,407	647,466	458,273
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	2,959,219	2,651,886	2,270,001
Operating Segments | SHOP | Third party capital management revenues
Revenues
Revenue from contracts with customers	0	0	0
Operating Segments | Triple-net leased properties
Revenues
Rental income	619,208	598,154	653,823
Interest and other income	0	0	0
Total revenues	619,208	598,154	653,823
Less:
Interest and other income	0	0	0
Property-level operating expenses	14,557	15,301	15,335
Third party capital management expenses	0	0	0
NOI	604,651	582,853	638,488
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
Operating Segments | Outpatient Medical And Research Portfolio
Revenues
Rental income	867,193	801,159	794,297
Interest and other income	0	0	0
Total revenues	869,708	803,607	802,681
Less:
Interest and other income	0	0	0
Property-level operating expenses	292,776	257,003	257,001
Third party capital management expenses	0	0	1,798
NOI	576,932	546,604	543,882
Income from loans and investments	0	0	0
Income from loans and investments	0	0	0
Operating Segments | Outpatient Medical And Research Portfolio | Resident fees and services
Revenues
Revenue from contracts with customers	0	0	0
Operating Segments | Outpatient Medical And Research Portfolio | Third party capital management revenues
Revenues
Revenue from contracts with customers	2,515	2,448	8,384
Non-Segment
Revenues
Rental income	0	0	0
Interest and other income	11,414	3,635	14,809
Total revenues	49,692	75,546	101,502
Less:
Interest and other income	11,414	3,635	14,809
Property-level operating expenses	0	0	0
Third party capital management expenses	6,101	6,194	2,635
NOI	32,177	65,717	84,058
Income from loans and investments	22,952	48,160	74,981
Income from loans and investments	22,952	48,160	74,981
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	$ 15,326	$ 23,751	$ 11,712