Real Estate - Schedule of Development in Process Activities (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) property	Dec. 31, 2019 USD ($) property	Dec. 31, 2018 USD ($) property
Property, Plant and Equipment [Line Items]
Number of properties under development | property	3	3	3
Real estate under development, beginning balance	$ 247,349	$ 253,402	$ 120,297
Transfers In	66,812	117,344
Capitalized Costs	8,062	25,580
Transfers Out	$ 80,927	$ 9,819
Core Portfolio
Property, Plant and Equipment [Line Items]
Number of properties under development | property	0	0	1
Real estate under development, beginning balance	$ 63,875	$ 60,863	$ 7,759
Transfers In	0	57,342
Capitalized Costs	3,012	5,581
Transfers Out	$ 0	$ 9,819
Fund Portfolio | Fund II
Property, Plant and Equipment [Line Items]
Number of properties under development | property	0	0	0
Real estate under development, beginning balance	$ 74,657	$ 10,703	$ 7,462
Transfers In	66,812	0
Capitalized Costs	3,612	3,241
Transfers Out	$ 6,470	$ 0
Fund Portfolio | Fund III
Property, Plant and Equipment [Line Items]
Number of properties under development | property	1	1	1
Real estate under development, beginning balance	$ 23,139	$ 36,240	$ 21,242
Transfers In	0	12,313
Capitalized Costs	70	2,685
Transfers Out	$ 13,171	$ 0
Fund Portfolio | Fund IV
Property, Plant and Equipment [Line Items]
Number of properties under development | property	2	2	1
Real estate under development, beginning balance	$ 85,678	$ 145,596	$ 83,834
Transfers In	0	47,689
Capitalized Costs	1,368	14,073
Transfers Out	$ 61,286	$ 0