Real Estate - Schedule of Development in Process Activities (Details) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2021 USD ($) Property	Dec. 31, 2020 USD ($) Property	Dec. 31, 2019 USD ($) Property
Property, Plant and Equipment [Line Items]
Number of properties under development | Property	2	3	3
Real estate under development, beginning balance	$ 217,620	$ 247,349	$ 253,402
Transfers In	0	66,812
Capitalized Costs	4,846	8,062
Transfers Out	$ (34,575)	$ (80,927)
Core Portfolio
Property, Plant and Equipment [Line Items]
Number of properties under development | Property	0	0	0
Real estate under development, beginning balance	$ 41,884	$ 63,875	$ 60,863
Transfers In	0	0
Capitalized Costs	1,222	3,012
Transfers Out	$ (23,213)	$ 0
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	$ 75,641	$ 74,657	$ 10,703
Transfers In	0	66,812
Capitalized Costs	984	3,612
Transfers Out	$ 0	$ (6,470)
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	$ 23,685	$ 23,139	$ 36,240
Transfers In	0	0
Capitalized Costs	546	70
Transfers Out	$ 0	$ (13,171)
Fund Portfolio | Fund IV
Property, Plant and Equipment [Line Items]
Number of properties under development | Property	1	2	2
Real estate under development, beginning balance	$ 76,410	$ 85,678	$ 145,596
Transfers In	0	0
Capitalized Costs	2,094	1,368
Transfers Out	$ (11,362)	$ (61,286)