Commitments and Contingencies (Details) $ in Millions	Jun. 30, 2018 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Amount of commitments for re-leasing costs, recurring capital expenditures and non-recurring building improvements	$ 15.9
Amount of commitments for construction contracts, which is expected to be paid in next twelve months	$ 14.3

The amount of contingent payments for re-leasing costs, recurring capital expenditures and non-recurring building improvements.

No definition available.

Name:	o_ReleasingCostsRecurringCapitalExpendituresAndNonRecurringBuildingImprovementsContingentPayments
Namespace Prefix:	o_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant