Real Estate Investments and Related Intangibles - Consolidated Joint Ventures Narrative (Details) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020 USD ($) property joint_venture	Dec. 31, 2019 USD ($) joint_venture property
Schedule of Equity Method Investments [Line Items]
Number of Properties | property	3,820
Total assets	$ 13,039,598	$ 13,280,680
Real estate investments, net	$ 10,780,729	11,249,623
Mortgages [Member]
Schedule of Equity Method Investments [Line Items]
Number of Properties | property	279
Aggregate balance outstanding	$ 1,334,098	$ 1,529,057
Joint ventures [Member]
Schedule of Equity Method Investments [Line Items]
Number of joint ventures | joint_venture	1	1
Total assets	$ 33,200	$ 32,500
Real estate investments, net	$ 29,700	$ 29,600
Joint ventures [Member] | Consolidated Properties [Member]
Schedule of Equity Method Investments [Line Items]
Number of Properties | property	1	1
Joint ventures [Member] | Consolidated Properties [Member] | Mortgages [Member]
Schedule of Equity Method Investments [Line Items]
Aggregate balance outstanding	$ 14,800	$ 14,300