Segment Information - Summary of Third-party Asset Management and Real Estate Services (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Third-party real estate services revenue, excluding reimbursements	$ 15,955	$ 14,237
Reimbursements revenue	13,761	13,454
Revenue from Contract with Customer, Including Reimbursements	29,716	27,691
Third-party real estate services expenses	28,814	28,066
Third-party real estate services revenue less expenses	902	(375)
Property management fees
Third-party real estate services revenue, excluding reimbursements	6,024	5,428
Asset management fees
Third-party real estate services revenue, excluding reimbursements	2,724	3,488
Leasing fees
Third-party real estate services revenue, excluding reimbursements	1,747	2,213
Development fees
Third-party real estate services revenue, excluding reimbursements	2,812	1,596
Construction management fees
Third-party real estate services revenue, excluding reimbursements	1,013	629
Other service revenue
Third-party real estate services revenue, excluding reimbursements	$ 1,635	$ 883