Investments in and Advances to Unconsolidated Affiliates - Core Portfolio - Additional Information (Details)						1 Months Ended	3 Months Ended	12 Months Ended
	Aug. 08, 2019 USD ($)	Jan. 24, 2019 USD ($) ft²	Mar. 28, 2018 USD ($)	Nov. 16, 2017 USD ($)	May 01, 2017 USD ($)	Apr. 29, 2016 USD ($)	Mar. 31, 2020 USD ($) ft²	Dec. 31, 2019 USD ($)	Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]
Purchase Price							$ 19,204,000	$ 324,339,000
Cost method investments							2,575,000	2,334,000
Notes receivable, net							$ 173,159,000	114,943,000
Acadia Brandywine Holdings, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage							22.22%
Brandywine Portfolio
Schedule of Equity Method Investments [Line Items]
Preferred return							$ 5,600,000
Core Portfolio
Schedule of Equity Method Investments [Line Items]
Purchase Price								146,435,000
Cost method investments							2,000,000.0
Gain (loss) on investment							$ 0
Equity method investment, ownership percentage by third party			14.11%	38.89%			24.78%
Equity method investment, ownership percentage				22.22%			75.22%		61.11%
Equity method investments			$ 22,300,000	$ 61,600,000			$ 223,088,000	225,907,000
Gain on equity method investment			12,700,000	34,500,000
Core Portfolio | Renaissance Portfolio
Schedule of Equity Method Investments [Line Items]
Percentage of voting interests acquired		20.00%
Equity method investment, ownership percentage							20.00%
Equity method investments							$ 30,947,000	$ 31,815,000
Core Portfolio | Fifth Wall Ventures Retail Fund, L.P.
Schedule of Equity Method Investments [Line Items]
Cost method investments	$ 1,800,000						$ 200,000
Maximum amount commitment to invest	$ 5,000,000.0
Cost method investment ownership percentage	5.00%
Core Portfolio | Brandywine Portfolio
Schedule of Equity Method Investments [Line Items]
Square footage of real estate property (in square feet) | ft²							1,000,000
Repayments of debt						$ 140,000,000.0
Note receivable exchanged			22,000,000.0		$ 16,000,000.0
Notes receivable, net					153,400,000		$ 38,700,000
Note receivable accrued interest			$ 300,000		$ 300,000
Core Portfolio | Brandywine Portfolio | Exchange Transaction One
Schedule of Equity Method Investments [Line Items]
Note receivable exchanged				16,000,000.0
Note receivable accrued interest				600,000
Core Portfolio | Brandywine Portfolio | Exchange Transaction Two
Schedule of Equity Method Investments [Line Items]
Note receivable exchanged				60,700,000
Note receivable accrued interest				$ 900,000
Core Portfolio | Market Square
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage by third party				38.89%	38.89%
Equity method investment, ownership percentage				22.22%	61.11%
Equity method investments					$ 16,300,000
Gain on equity method investment					$ 9,800,000
Core Portfolio | Washington, D.C. | Renaissance Portfolio
Schedule of Equity Method Investments [Line Items]
Square footage of real estate property (in square feet) | ft²		7,300
Purchase Price		$ 10,700,000
Purchase price less the assumption of the outstanding mortgage		$ 4,700,000