Supplemental Disclosures of Cash Flow Information - Narrative (Details) - USD ($) $ in Thousands				9 Months Ended
	Mar. 28, 2019	Apr. 30, 2018	Mar. 30, 2018	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Jan. 01, 2019
Supplemental Disclosures of Cash Flow Information
Cash paid for interest				$ 224,700	$ 214,200
Cash paid for income taxes				8,100	$ 3,600
Non-cash activities
Non-refundable deposits from 2019 applied to acquisitions				13,800
Lease liabilities				117,148		$ 122,285
Right-of-use assets				114,748		$ 120,533
ASU 2016-02
Non-cash activities
Lease liabilities							$ 132,000
Right-of-use assets							$ 132,000
Realty Income, L.P.
Non-cash activities
Number of partnership units issued (in units)	89,322	131,790	242,007		89,322
Shares issued in conjunction with acquisitions					$ 6,300
Derivative
Non-cash activities
Decrease in fair value of net derivative liabilities				$ 26,000