Real Estate Investments and Related Intangibles - Consolidated Joint Ventures Narrative (Details) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2020 USD ($) property joint_venture	Dec. 31, 2019 USD ($) property joint_venture
Schedule of Equity Method Investments [Line Items]
Number of Properties | property	3,836
Total assets	$ 13,321,182	$ 13,280,680
Real estate investments, net	$ 10,958,484	11,249,623
Mortgages [Member]
Schedule of Equity Method Investments [Line Items]
Number of Properties | property	314
Aggregate balance outstanding	$ 1,396,432	$ 1,529,057
Joint ventures [Member]
Schedule of Equity Method Investments [Line Items]
Number of joint ventures | joint_venture	1	1
Total assets	$ 33,600	$ 32,500
Real estate investments, net	$ 30,000	$ 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	$ 15,200	$ 14,300