Loans Receivable - Schedule of Loans Receivable (Details) - USD ($)	Sep. 30, 2024	Feb. 29, 2024	Dec. 31, 2023	Dec. 31, 2022
Financing Receivable, Allowance for Credit Loss [Line Items]
Unamortized discounts and fees	$ (24,274,000)		$ (131,000)
Reserve for loan losses	(9,983,000)		(2,830,000)	$ (8,280,000)
Loans receivable, net	677,590,000		218,450,000
Loans and leases receivable, remaining commitments	56,000,000
Unamortized discount	4,000,000
Sunrise Senior Housing Portfolio
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans receivable, net	58,000,000		131,000,000
Loans and leases receivable, remaining commitments		$ 0	29,000,000
Outpatient Medical Buildings
Financing Receivable, Allowance for Credit Loss [Line Items]
Unamortized discount	19,000,000
Secured loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing receivable, gross	618,216,000		178,678,000
Reserve for loan losses	(8,879,000)		(2,830,000)	$ (8,280,000)
CCRC resident loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing receivable, gross	56,411,000		42,733,000
Mezzanine loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing receivable, gross	$ 37,220,000		$ 0