Fair Value (Assets Measured on a Non-recurring Basis) (Details) - Fair Value, Measurements, Nonrecurring $ in Thousands	Mar. 31, 2020 USD ($)
Measurement Input, Cap Rate | Discounted cash flow analysis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value capitalization rate	0.100
Outlet Collection At Riverwalk
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Outlet Collection at Riverwalk	$ 46,794
Outlet Collection At Riverwalk | Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Outlet Collection at Riverwalk	0
Outlet Collection At Riverwalk | Fair Value Measurements Using Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Outlet Collection at Riverwalk	0
Outlet Collection At Riverwalk | Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Outlet Collection at Riverwalk	$ 46,794