Financing Arrangement - Narrative (Details) ft² in Thousands, $ in Thousands			9 Months Ended
	Jun. 27, 2019 USD ($)	Sep. 30, 2009 ft²	Sep. 30, 2019 USD ($) $ / ft²	Sep. 30, 2018 USD ($)	Dec. 31, 2018 $ / ft²
Schedule of Joint Ventures [Line Items]
Terminal capitalization rate			5.00%		4.80%
Discount rate			6.00%		5.80%
Distributions, pro rata share of the excess loan proceeds | $	$ 27,945		$ 27,945	$ 0
Chandler Fashion Center
Schedule of Joint Ventures [Line Items]
Additional borrowing | $	$ 256,000
Financing Arrangement | Minimum
Schedule of Joint Ventures [Line Items]
Market rent per square foot | $ / ft²			35		35
Financing Arrangement | Maximum
Schedule of Joint Ventures [Line Items]
Market rent per square foot | $ / ft²			115		115
Financing Arrangement | Chandler Freehold
Schedule of Joint Ventures [Line Items]
Percentage of loan assumed by third party		49.90%
Financing Arrangement | Chandler Fashion Center
Schedule of Joint Ventures [Line Items]
Property area (in square feet) | ft²		1,318
Financing Arrangement | Freehold Raceway Mall
Schedule of Joint Ventures [Line Items]
Property area (in square feet) | ft²		1,673