Investments in Partnerships - Summary of Mortgage Loans Secured by Our Unconsolidated Properties (Details) - USD ($) $ in Thousands	1 Months Ended
	Mar. 31, 2018	Feb. 28, 2018	Oct. 31, 2017	Dec. 31, 2019	Dec. 31, 2018
Partnership Mortgage Loan Activity [Line Items]
Mortgage loans payable, net				$ 899,753	$ 1,047,906
Pavilion at Market East
Partnership Mortgage Loan Activity [Line Items]
Mortgage loans payable, net		$ 8,300
Debt instrument, maturity month and year		2021-02
Pavilion at Market East | LIBOR
Partnership Mortgage Loan Activity [Line Items]
Stated Interest Rate		2.85%
Gloucester Premium Outlets
Partnership Mortgage Loan Activity [Line Items]
Mortgage loans payable, net	$ 86,000
Debt instrument, maturity month and year	2022-03
Gloucester Premium Outlets | LIBOR
Partnership Mortgage Loan Activity [Line Items]
Stated Interest Rate	1.50%
Lehigh Valley Associates, LP
Partnership Mortgage Loan Activity [Line Items]
Mortgage loans payable, net			$ 200,000
Fixed interest rate			4.06%
Debt instrument, maturity month and year			2027-11