Investments in Unconsolidated Joint Ventures - Summary of Company's Investments in Unconsolidated Joint Ventures (Detail)	6 Months Ended
	Jun. 30, 2018 ft² Property
Income Statement Equity Method Investments [Line Items]
Number of properties | Property	26
Total GLA | ft²	4,660,300
General Growth Properties, Inc. I [Member]
Income Statement Equity Method Investments [Line Items]
Seritage % Ownership	50.00%
Number of properties | Property	4
Total GLA | ft²	550,600
General Growth Properties, Inc. II [Member]
Income Statement Equity Method Investments [Line Items]
Seritage % Ownership	50.00%
Number of properties | Property	5
Total GLA | ft²	1,175,600
The Macerich Company [Member]
Income Statement Equity Method Investments [Line Items]
Seritage % Ownership	50.00%
Number of properties | Property	9
Total GLA | ft²	1,575,600
Simon Property Group Inc [Member]
Income Statement Equity Method Investments [Line Items]
Seritage % Ownership	50.00%
Number of properties | Property	5
Total GLA | ft²	872,200
Invesco Real Estate [Member]
Income Statement Equity Method Investments [Line Items]
Seritage % Ownership	50.10%
Number of properties | Property	1
Total GLA | ft²	96,400
Invesco Real Estate II [Member]
Income Statement Equity Method Investments [Line Items]
Seritage % Ownership	50.00%
Number of properties | Property	1
Total GLA | ft²	226,200
First Washington Realty [Member]
Income Statement Equity Method Investments [Line Items]
Seritage % Ownership	50.00%
Number of properties | Property	1
Total GLA | ft²	163,700