Investments in and Advances to Joint Ventures - Summary of Preferred investments (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) ShoppingCenter	Dec. 31, 2017 USD ($)	Dec. 31, 2015 USD ($) ShoppingCenter	Oct. 31, 2014 USD ($) ShoppingCenter
Schedule Of Equity Method Investments [Line Items]
Preferred Investment, Valuation Allowance	$ (72.4)	$ (61.0)
BRE DDR III [Member]
Schedule Of Equity Method Investments [Line Items]
Preferred Investment, Valuation Allowance	(58.7)
BRE DDR IV [Member]
Schedule Of Equity Method Investments [Line Items]
Preferred Investment, Valuation Allowance	$ (13.7)
BRE DDR Retail Holdings Joint Venture Acquisitions [Member] \| BRE DDR III [Member]
Schedule Of Equity Method Investments [Line Items]
Unconsolidated Joint Venture Partner Formation Date Month And Year	2014
Preferred Investment (Principal)	$ 191.2			$ 300.0
Preferred Investment, Valuation Allowance	(58.7)
Preferred Investment, Net of Reserve	$ 132.5
Properties Owned \| ShoppingCenter	16			70
BRE DDR Retail Holdings Joint Venture Acquisitions [Member] \| BRE DDR IV [Member]
Schedule Of Equity Method Investments [Line Items]
Unconsolidated Joint Venture Partner Formation Date Month And Year	2015
Preferred Investment (Principal)	$ 66.7		$ 82.6
Preferred Investment, Valuation Allowance	(13.7)
Preferred Investment, Net of Reserve	$ 53.0
Properties Owned \| ShoppingCenter	5		6
BRE DDR Retail Holdings Joint Venture Acquisitions [Member] \| BRE DDR III and IV [Member]
Schedule Of Equity Method Investments [Line Items]
Preferred Investment (Principal)	$ 257.9		$ 382.6
Preferred Investment, Valuation Allowance	(72.4)
Preferred Investment, Net of Reserve	$ 185.5