Investment in Unconsolidated Real Estate Ventures - Summary of Results of Operations of Real Estate Ventures with Interests (Parenthetical) (Details)		Mar. 31, 2019	Mar. 31, 2018
evo at Cira Centre South [Member]
Schedule Of Equity Method Investments [Line Items]
Ownership percentage	[1]	50.00%	50.00%
Unconsolidated Real Estate Ventures [Member] | Minimum [Member]
Schedule Of Equity Method Investments [Line Items]
Ownership percentage		15.00%	25.00%
Unconsolidated Real Estate Ventures [Member] | Maximum [Member]
Schedule Of Equity Method Investments [Line Items]
Ownership percentage		70.00%	70.00%

[1] The Company sold its 50% ownership interest in evo at Cira Centre South Venture during the first quarter of 2018.