Face (par) amount of debt instrument at time of issuance.

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Senior Notes Payable and Other Debt - Mortgages (Details) $ in Thousands, $ in Millions		1 Months Ended	12 Months Ended
	Sep. 21, 2021 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($) property senior_housing loan	Dec. 31, 2020 USD ($)	Sep. 30, 2021 CAD ($)
Debt Instrument [Line Items]
Weighted average maturity period of mortgage loans			4 years 2 months 12 days
Unamortized fair value adjustment			$ 32,888	$ 12,618
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			$ 12,027,544	11,895,412
New Senior Investment Group Inc. Acquisition
Debt Instrument [Line Items]
Mortgage debt assumed in transaction	$ 482,500
Mortgage Loans and Other
Debt Instrument [Line Items]
Number of mortgage loans \| loan			112
Principal amount of debt			$ 2,400,000
Long-Term Debt, Number Of Properties Secured \| property			102
Number of mortgage loans with fixed interest rate \| senior_housing			95
Mortgage loans with fixed interest rate			$ 2,100,000
Number of mortgage loans with variable interest rate \| senior_housing			17
Mortgage loans with variable interest rate			$ 370,000
Repayments of debt			$ 284,700	$ 60,900
Mortgage Loans and Other \| New Senior Investment Group Inc. Acquisition
Debt Instrument [Line Items]
Mortgage debt assumed in transaction		$ 482,500
Mortgage Loans and Other \| New Senior Investment Group Inc. Acquisition
Debt Instrument [Line Items]
Unamortized fair value adjustment					$ 25.4
Mortgage Loans and Other \| Fixed Rate Debt
Debt Instrument [Line Items]
Weighted interest rate			3.60%
Mortgage Loans and Other \| Variable Rate Debt
Debt Instrument [Line Items]
Weighted interest rate			1.70%
Mortgage Loans and Other \| Minimum
Debt Instrument [Line Items]
Long-term debt, percentage bearing fixed interest			1.99%
Long-term debt, percentage bearing variable interest			0.08%
Mortgage Loans and Other \| Maximum
Debt Instrument [Line Items]
Long-term debt, percentage bearing fixed interest			13.01%
Long-term debt, percentage bearing variable interest			2.85%