Related Party Transactions - Schedule of fees charged to unconsolidated joint ventures (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Management fees
Related Party Transaction [Line Items]
Revenues	$ 9,978	$ 11,052	$ 29,277	$ 32,090
Unconsolidated Joint Ventures and Third Party Managed Properties
Related Party Transaction [Line Items]
Revenues	9,034	8,941	24,991	25,261
Unconsolidated Joint Ventures and Third Party Managed Properties | Management fees
Related Party Transaction [Line Items]
Revenues	4,746	4,971	13,897	14,366
Unconsolidated Joint Ventures and Third Party Managed Properties | Development and leasing fees
Related Party Transaction [Line Items]
Revenues	$ 4,288	$ 3,970	$ 11,094	$ 10,895