Summary of Significant Accounting Policies - Additional Information (Detail) $ / shares in Units, $ in Millions		3 Months Ended
	Dec. 14, 2017 ShoppingCenter	Mar. 31, 2018 USD ($) JointVenture $ / shares	Mar. 31, 2017 $ / shares	Dec. 31, 2017 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Maximum exposure to losses associated with VIEs | $		$ 240.1		$ 284.1
Common share dividends declared per share | $ / shares		$ 0.19	$ 0.19
Variable Interest Entity, Not Primary Beneficiary [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of unconsolidated joint ventures | JointVenture		2
Retail Value Inc. [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of shopping centers the company intended to spinoff	50
Gross asset value | $		$ 2,800.0
U.S. [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of shopping centers the company intended to spinoff	38
Puerto Rico [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of shopping centers the company intended to spinoff	12