Commitments and Contingencies - Narrative (Details) $ in Millions	Jun. 30, 2025 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Total leasing commitment	$ 35.8
Tenant improvement allowance	29.1
Rent concession	$ 6.7

Lessor, Operating Lease, Restricted Cash Included In Commitment Outstanding

No definition available.

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Namespace Prefix:	onl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant