Noncontrolling Interests - Narrative (Details) $ in Thousands	1 Months Ended				12 Months Ended
	Dec. 31, 2019 property	Jul. 31, 2019 USD ($)	Jan. 31, 2019 USD ($) shares	Dec. 31, 2018 entity	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 property entity
Noncontrolling interests
Conversion ratio					1
Number of properties acquired | property	9							2
Number of joint ventures controlling interest acquired | entity								2
Number of entities in which all outstanding minority interests were acquired | entity				1
Redemption of partnership units					$ 21,123	$ 2,752	$ 0
Term Loans | $70 million senior unsecured term loan
Noncontrolling interests
Repayments of long-term debt			$ 70,000
Tau Operating Partnership
Noncontrolling interests
Number of partnership units redeemed (in units) | shares			317,022
Third-party partnership ownership interest (as a percent)			0.11%
Ownership interest (as a percent)			100.00%
Redemption of partnership units			$ 20,200
Excess of redemption of units over carrying value as reduction to common stock and paid in capital			$ 6,900
Realty Income, L.P.
Noncontrolling interests
Third-party partnership ownership interest (as a percent)	1.90%				1.90%
Ownership interest (as a percent)	98.10%				98.10%
Joint Venture
Noncontrolling interests
Ownership interest (as a percent)	89.90%				89.90%
Other Noncontrolling Interest One
Noncontrolling interests
Redemption of partnership units		$ 900