Investments in Partnerships - Mortgage Loans of Unconsolidated Properties (Details)	12 Months Ended
	Dec. 31, 2019 Property
Mortgage Loan
Mortgage Loans On Real Estate [Line Items]
Debt Instrument, weighted average interest rate	4.04%
Mortgage Loan | Fixed Interest Rate
Mortgage Loans On Real Estate [Line Items]
Debt Instrument, weighted average interest rate	4.08%
Mortgage Loan | Fixed Interest Rate | Minimum
Mortgage Loans On Real Estate [Line Items]
Debt instrument, interest rate during period	3.88%
Mortgage Loan | Fixed Interest Rate | Maximum
Mortgage Loans On Real Estate [Line Items]
Debt instrument, interest rate during period	5.95%
Mortgage Loan | Variable Interest Rate
Mortgage Loans On Real Estate [Line Items]
Debt Instrument, weighted average interest rate	3.94%
Unconsolidated Properties
Mortgage Loans On Real Estate [Line Items]
Number of properties securing mortgage debt	7
Number of fixed rate mortgage loans payable	5
Number of variable rate mortgage loans payable	2
Unconsolidated Properties | Mortgage Loan
Mortgage Loans On Real Estate [Line Items]
Property under development	1
Mortgage loan due date	2027
Debt Instrument, weighted average interest rate	4.43%
Unconsolidated Properties | Mortgage Loan | Fixed Interest Rate
Mortgage Loans On Real Estate [Line Items]
Debt Instrument, weighted average interest rate	4.55%
Unconsolidated Properties | Mortgage Loan | Fixed Interest Rate | Minimum
Mortgage Loans On Real Estate [Line Items]
Debt instrument, interest rate during period	4.06%
Unconsolidated Properties | Mortgage Loan | Fixed Interest Rate | Maximum
Mortgage Loans On Real Estate [Line Items]
Debt instrument, interest rate during period	5.56%
Unconsolidated Properties | Mortgage Loan | Variable Interest Rate
Mortgage Loans On Real Estate [Line Items]
Debt Instrument, weighted average interest rate	3.37%
Unconsolidated Properties | Mortgage Loan | Variable Interest Rate | Minimum
Mortgage Loans On Real Estate [Line Items]
Debt instrument, interest rate during period	3.19%
Unconsolidated Properties | Mortgage Loan | Variable Interest Rate | Maximum
Mortgage Loans On Real Estate [Line Items]
Debt instrument, interest rate during period	4.60%