v3.25.4

Debt and Preferred Equity Investments - Additional Information (Details)	12 Months Ended
	Dec. 31, 2025 USD ($) investment segment	Dec. 31, 2024 USD ($) investment segment	Dec. 31, 2023 USD ($)
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of investments, fully reserved \| investment	1	1
Number of investments, nonperforming \| investment	1
Carrying value at fixed rate	$ 168,358,000	$ 303,726,000
Number of portfolio segments of financial receivables (segment) \| segment	1	1
Loan loss and other investment reserves, net of recoveries	$ (71,326,000)	$ 0	$ 6,890,000
Other Assets
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Loan loss and other investment reserves, net of recoveries	0	0
Other Assets
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Total after allowance for loan loss	15,900,000	23,700,000
Financing Receivables, Equal to Greater than 90 Days Past Due
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Carrying value at fixed rate	$ 0	$ 0

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SL GREEN REALTY CORP 10-K