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Investment in Unconsolidated Joint Venture - Additional Information (Detail) - USD ($) $ in Millions				3 Months Ended		9 Months Ended
	Mar. 18, 2025	Oct. 18, 2017	Jun. 01, 2017	Mar. 31, 2025	Mar. 31, 2024	Sep. 30, 2024	Sep. 13, 2024	Oct. 30, 2013
Schedule of Equity Method Investments [Line Items]
Unitholders distribute amount	$ 69.7
Cravath, Swaine & Moore LLP [Member]
Schedule of Equity Method Investments [Line Items]
Lease expiration date				Aug. 31, 2024
Worldwide Plaza [Member]
Schedule of Equity Method Investments [Line Items]
Ownership percentage				50.10%		50.10%		48.90%
Aggregate cost			$ 276.7					$ 220.1
Agreed upon value								1,300.0
Notes payable								$ 875.0
Additional acquire percentage			49.90%
Purchase obligation			$ 1,400.0
Mortgage notes payable			$ 875.0
Joint venture partner's right to maintain minimum ownership percentage			1.20%
Debt refinance amount		$ 1,200.0
Cash received from sale and excess proceeds from financing		446.5
Defeasance and prepayment costs		108.3
Reserved amount		$ 90.7
Debt blended rate		3.98%
Maturity date						2027-11
Interest payment							$ 0.8
Property selling percentage				100.00%
Option to purchase percentage of property				100.00%
Property purchase option period				45 days
Re-offer property selling percentage				92.50%
Worldwide Plaza [Member] \| SL Green Realty Corp. and RXR Realty LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership percentage		48.70%
Liquidation value of property		$ 1,725.0
Worldwide Plaza [Member] \| Nomura Holdings America, Inc [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of total cash rent income				58.20%
Mezzanine First Loan [Member] \| Worldwide Plaza [Member]
Schedule of Equity Method Investments [Line Items]
Subsidiary borrowings loan amount							$ 190.0
Liquidation Value [Member] \| Worldwide Plaza [Member]
Schedule of Equity Method Investments [Line Items]
Ownership percentage			98.80%
Liquidation Value [Member] \| Worldwide Plaza [Member] \| Nomura Holdings America, Inc [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of total annualized rental income					29.40%
Liquidation Value [Member] \| Worldwide Plaza [Member] \| Cravath, Swaine & Moore LLP [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of total annualized rental income					48.10%