Debt - Mortgage and Other Notes Payable - Additional Information (Details) $ in Thousands		1 Months Ended	3 Months Ended	12 Months Ended
	Jul. 15, 2023 USD ($) Mortgage	Jan. 31, 2024 USD ($)	Sep. 30, 2022 USD ($)	Dec. 31, 2023 USD ($) Mortgage	Dec. 31, 2022 USD ($) Mortgage	Jun. 30, 2022 USD ($)
Debt Instrument [Line Items]
Notes receivable, net				$ 124,949	$ 123,903
Interest expense reduced	$ 700
Number of mortgage loans | Mortgage	0
Maximum borrowing capacity				900,000
Initial term for mortgage loan			3 years
Repayments of debt					22,700
Scheduled principal payment				7,700
Short-Term Debt, Refinanced, Amount				111,400
Disposed of by sale
Debt Instrument [Line Items]
Repayments of debt					12,300
Discontinued Operations Disposed Of By Sale Under Fund Mortgage
Debt Instrument [Line Items]
Repayments of debt					97,600
Mortgages
Debt Instrument [Line Items]
Notes receivable, net				$ 32,200	$ 42,400
Number of mortgage loans | Mortgage				5	10
Mortgage Loan Principal Reduction Amount					$ 8,600
Maximum borrowing capacity					$ 42,200
Repayments of debt				$ 5,800
Maturity date					Dec. 29, 2023
Number of properties collateralized | Mortgage				33	31
Mortgages | Subsequent Event
Debt Instrument [Line Items]
Scheduled principal payment		$ 3,900
Mortgages | Subscription Line
Debt Instrument [Line Items]
Notes receivable, net				$ 150,800	$ 280,600
Mortgage Loan Principal Amount				$ 2,700	4,600
Mortgage Loan Interest Reserve					$ 4,200
Refinanced Mortgages
Debt Instrument [Line Items]
Number of mortgage loans | Mortgage				4
SOFR
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	3.65%		2.61%		2.56%
Fund II
Debt Instrument [Line Items]
Single Mortgage Loan			$ 198,000
Proceeds from Sale of Mortgage Loans Held-for-sale			132,300
Loans Payable			26,000
Fund II | Mortgages
Debt Instrument [Line Items]
Maximum borrowing capacity			$ 257,900
Maturity date			Jul. 10, 2027
Debt Instrument, Basis Spread on Variable Rate			4.00%
Fund II | Secured Debt
Debt Instrument [Line Items]
Maximum borrowing capacity			$ 50,000
Fund II | Unsecured Term Loan
Debt Instrument [Line Items]
Maximum borrowing capacity			40,000
Fund IV
Debt Instrument [Line Items]
Repayments of debt					$ 17,000
Loan accrues default interest	4.00%
Fund IV | Mortgages
Debt Instrument [Line Items]
Mortgage Loan Principal Reduction Amount				$ 3,000
Maximum borrowing capacity				$ 36,200
Maturity date				Mar. 31, 2025
Fund IV | 146 Geary Street, San Francisco, CA
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 19,300
Share value matured debt service coverage ratio	$ 4,500
Fund IV | 146 Geary Street, San Francisco, CA | Minimum
Debt Instrument [Line Items]
Impairment charges at the company's share				$ 3,700
Fund IV | 146 Geary Street, San Francisco, CA | Maximum
Debt Instrument [Line Items]
Impairment charges at the company's share				$ 900
Fund V
Debt Instrument [Line Items]
Number of mortgage loans | Mortgage				3
Maximum borrowing capacity				$ 29,200
Share value below debt service coverage ratio				5,900
Fund V | Mortgages
Debt Instrument [Line Items]
Share value below debt service coverage ratio				25,500
Short-Term Debt, Refinanced, Amount				127,100
Core Portfolio
Debt Instrument [Line Items]
Notes receivable, net					13,500	$ 16,000
Derivative, notional amount				$ 856,000
Short-Term Debt, Refinanced, Amount			$ 25,400
Core Portfolio | Disposed of by sale
Debt Instrument [Line Items]
Scheduled principal payment					$ 7,500