Loans Receivable - Narrative (Details)		1 Months Ended									3 Months Ended		12 Months Ended	24 Months Ended
	Mar. 01, 2024 USD ($) loan	Mar. 31, 2025 USD ($) extension_option	Jan. 31, 2025 USD ($) loan extension_option	Nov. 30, 2024 USD ($) property	Jul. 31, 2024 USD ($) property extension_option	May 31, 2024 USD ($)	Feb. 29, 2024 USD ($)	Jan. 31, 2024 USD ($)	Feb. 28, 2023 USD ($)	Jan. 31, 2021 USD ($) facility	Mar. 31, 2025 USD ($)	Mar. 31, 2024 USD ($) property	Dec. 31, 2024 USD ($) property	Dec. 31, 2022 USD ($)
Loans Receivable:
Loans receivables, acquired	$ 124,000,000
Financing receivable, after allowance for credit loss		$ 698,525,000									$ 698,525,000		$ 717,190,000
Credit loss reserve on unfunded loan commitments		2,200,000									2,200,000		2,900,000
Sunrise Senior Housing Portfolio
Loans Receivable:
Loans receivable, outstanding balance							$ 131,000,000
Number of assets to be sold | facility										32
Proceeds from sale of property										$ 664,000,000
Investments in loans receivable										410,000,000
Capital expenditure funding, amount committed										$ 92,000,000
Capital expenditure funding, cost of capital, percent committed										65.00%
Proceeds from the collection of loans receivable						$ 5,000,000	$ 69,000,000							$ 291,000,000
Financing receivable, after allowance for credit loss		58,000,000									58,000,000		58,000,000
Sunrise Senior Housing Portfolio | Secured Overnight Financing Rate (SOFR)
Loans Receivable:
Loans receivable, conversion of basis spread on variable rate							0.10%
Loans receivable, floor rate							9.00%
Sunrise Senior Housing Portfolio | Secured Overnight Financing Rate (SOFR), First Two Years
Loans Receivable:
Loans receivable, basis spread on variable rate							4.00%
Loan receivable, extended maturity term							2 years
Sunrise Senior Housing Portfolio | Secured Overnight Financing Rate (SOFR), Last Eighteen Months
Loans Receivable:
Loans receivable, basis spread on variable rate							5.00%
Loan receivable, extended maturity term							18 months
SHOP
Loans Receivable:
Number of assets to be sold | facility										16
Proceeds from sale of property										$ 230,000,000
Investments in loans receivable										$ 150,000,000
Outpatient Medical Buildings
Loans Receivable:
Proceeds from sale of property					$ 674,000,000							$ 29,000,000	674,000,000
Investments in loans receivable					$ 405,000,000								$ 405,000,000
Number of properties sold | property					59							2	59
Loans receivable, number of extensions | extension_option					2
Loan receivable, period of extensions					12 months
Proceeds from loan originations					$ 1,000,000
Mark-to-market discount of real estate													$ 21,000,000
Noncash or part noncash, interest income											2,000,000
Other non-reportable | Brookedale MTCA | Lessor Asset Under Operating Lease | CCRC JV
Loans Receivable:
Financing receivable, after allowance for credit loss		61,000,000									61,000,000		61,000,000
Two Outpatient Medical Buildings
Loans Receivable:
Proceeds from sale of property				$ 23,000,000									23,000,000
Investments in loans receivable				$ 14,000,000									$ 14,000,000
Number of properties sold | property				2									2
Minimum | Outpatient Medical Buildings
Loans Receivable:
Loans receivable, interest rate					0.060
Maximum | Outpatient Medical Buildings
Loans Receivable:
Loans receivable, interest rate					0.065
Secured Mortgage Loans
Loans Receivable:
Number of loans | loan	9
Loans receivable, outstanding balance	$ 89,000,000
Receivable with imputed interest		600,000									600,000		$ 1,000,000
Secured Mortgage Loans | Other
Loans Receivable:
Number of loans | loan			1
Proceeds from the collection of loans receivable			$ 15,000,000
Secured Mortgage Loans | SHOP
Loans Receivable:
Loans receivable, outstanding balance								$ 48,000,000
Proceeds from the collection of loans receivable									$ 102,000,000
Loans receivable, floor rate								12.00%
Loans receivable, extension fee								$ 1,000,000
Secured Mortgage Loans | SHOP | Secured Overnight Financing Rate (SOFR)
Loans Receivable:
Loans receivable, conversion of basis spread on variable rate								0.11%
Loans receivable, floor rate								7.00%
Secured Mortgage Loans | Lab | Other
Loans Receivable:
Loans receivable, outstanding balance			$ 75,000,000
Loans receivable, interest rate			0.08
Loans receivable, number of extensions | extension_option			1
Loan receivable, period of extensions			12 months
Payments for loans receivable											$ 28,000,000
Secured Mortgage Loans | Outpatient medical | Other
Loans Receivable:
Loans receivable, outstanding balance		$ 41,000,000
Loans receivable, interest rate		0.083									0.083
Loans receivable, number of extensions | extension_option		2
Loan receivable, period of extensions		12 months
Payments for loans receivable											$ 4,000,000
Secured Mortgage Loans | Minimum
Loans Receivable:
Loans receivable, interest rate	0.0700
Secured Mortgage Loans | Maximum
Loans Receivable:
Loans receivable, interest rate	0.1000
Mezzanine loans
Loans Receivable:
Number of loans | loan	10
Loans receivable, outstanding balance	$ 36,000,000
Receivable with imputed interest		$ 2,000,000									2,000,000		2,000,000
Mezzanine loans | Other
Loans Receivable:
Number of loans | loan			1
Loans receivable, outstanding balance													$ 15,000,000
Loans receivable, interest rate													0.1100
Proceeds from the collection of loans receivable			$ 1,000,000
Mezzanine loans | Minimum
Loans Receivable:
Loans receivable, interest rate	0.0800
Mezzanine loans | Maximum
Loans Receivable:
Loans receivable, interest rate	0.1000
Construction Loan Commitments | Other
Loans Receivable:
Loans receivable, outstanding balance													$ 36,000,000
Loans receivable, interest rate													0.0800
Payments for loans receivable											$ 0		$ 0