Investments in Unconsolidated Real Estate Ventures - Financial Information - Narrative (Details) - USD ($)	1 Months Ended		12 Months Ended
	Oct. 31, 2020	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]
Gain (loss) on sale of real estate			$ 59,477,000	$ 104,991,000	$ 52,183,000
Landmark | Woodglen
Schedule of Equity Method Investments [Line Items]
Gain (loss) on sale of real estate		$ (3,000,000.0)	(3,000,000.0)
CBREI Venture | Pickett Industrial Park
Schedule of Equity Method Investments [Line Items]
Gain (loss) on sale of real estate	$ 800,000		800,000
Canadian Pension Plan Investment Board (CPPIB) | The Warner
Schedule of Equity Method Investments [Line Items]
Gain (loss) on sale of real estate					20,600,000
Landmark Venture Partner | Landmark | Woodglen
Schedule of Equity Method Investments [Line Items]
Gain (loss) on sale of real estate			(16,400,000)
CPPIB Venture Partner | Canadian Pension Plan Investment Board (CPPIB) | The Warner
Schedule of Equity Method Investments [Line Items]
Gain (loss) on sale of real estate					$ 32,500,000
CBREI Venture Partner | CBREI Venture | Pickett Industrial Park
Schedule of Equity Method Investments [Line Items]
Gain (loss) on sale of real estate			$ 8,000,000.0