Supplemental Disclosures of Cash Flow Information - Narrative (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Mar. 28, 2019	Jan. 01, 2019	Apr. 30, 2018	Mar. 30, 2018	Jun. 27, 2013
Supplemental Disclosures of Cash Flow Information
Cash paid for interest	$ 214,200	$ 197,200
Cash paid for income taxes	3,600	4,000
Non-cash activities
Lease liabilities	124,349			$ 132,000
Right-of-use assets				$ 132,000
Acquisition of property using funds held in non-refundable escrow account		7,500
Properties under development
Supplemental Disclosures of Cash Flow Information
Interest capitalized to properties under development	$ 549	$ 234
Realty Income, L.P.
Non-cash activities
Number of partnership units issued (in units)	89,322	373,797	89,322		131,790	242,007	534,546
Shares issued in conjunction with acquisition	$ 6,300
Value of partnership units issued		$ 18,800