SENIOR NOTES PAYABLE AND OTHER DEBT - Mortgages (Details) $ in Thousands, $ in Millions		1 Months Ended	12 Months Ended
	May 01, 2023 USD ($) property	Mar. 31, 2023 CAD ($)	Dec. 31, 2023 USD ($) senior_housing property loan	Dec. 31, 2022 USD ($)	Dec. 31, 2023 CAD ($) property loan	Oct. 31, 2023 USD ($)	Jul. 31, 2023 USD ($) property	Jun. 30, 2023 property
Debt Instrument [Line Items]
Weighted average maturity period of mortgage loans			4 years 9 months 18 days
Unamortized fair value adjustment			$ 17,081	$ 23,535
Minimum percentage of total unencumbered assets as a percentage of unsecured debt required to be maintained (as a percent)			150.00%
Senior notes payable and other debt			$ 13,490,896	12,296,780
Mortgage Loans and Other
Debt Instrument [Line Items]
Number of mortgage loans | loan			147		147
Principal amount of debt		$ 271.8	$ 3,200,000		$ 93.5		$ 426,800
Number of properties securing debt | property	153		140		140		19	14
Number of mortgage loans with fixed interest rate | senior_housing			131
Mortgage loans with fixed interest rate			$ 2,800,000
Number of mortgage loans with variable interest rate | senior_housing			16
Mortgage loans with variable interest rate			$ 418,300
Repayments of debt			$ 50,900	$ 600
Number Of Properties Related To Debt Repayment | property			5		5
Interest rate							5.91%
Financing Receivable, Accrued Interest, before Allowance for Credit Loss						$ 32,000
Debt Instrument, Interest Rate, Effective Percentage			1.31%		1.31%	5.60%
Senior notes payable and other debt						$ 394,800
Mortgage Loans and Other | Nonrecourse
Debt Instrument [Line Items]
Principal amount of debt	$ 1,000,000
Mortgage Loans and Other | London Interbank Offered Rate (LIBOR) 1
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.84%
Mortgage Loans and Other | Canadian Dollar Offered Rate (CDOR)
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		88.00%
Mortgage Loans and Other | Fixed Rate Debt
Debt Instrument [Line Items]
Weighted interest rate			4.20%		4.20%
Mortgage Loans and Other | Variable Rate Debt
Debt Instrument [Line Items]
Weighted interest rate			6.10%		6.10%
Mortgage Loans and Other | Minimum
Debt Instrument [Line Items]
Long-term debt, percentage bearing fixed interest			2.24%		2.24%
Long-term debt, percentage bearing variable interest			3.61%		3.61%
Mortgage Loans and Other | Maximum
Debt Instrument [Line Items]
Long-term debt, percentage bearing fixed interest			13.02%		13.02%
Long-term debt, percentage bearing variable interest			7.70%		7.70%