Investments in Real Estate Partnerships - Schedule of Dispositions (Details) - Unconsolidated Properties [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) property	Dec. 31, 2019 USD ($) property	Dec. 31, 2018 USD ($) property
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Sale of Equity Method Investments	$ 27,974	$ 142,754	$ 27,144
Equity Method Investment, Realized Gain (Loss) on Disposal	7,147	64,798	16,624
Equity Method Investment, Realized Gain (Loss) on Disposal, Parent Company's Share	$ 2,413	$ 29,422	$ 3,608
Operating Segments [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties sold | property	2	4	1
Land [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties sold | property	0	0	2