Investments in Unconsolidated Joint Ventures - Summary of Company's Investments in Unconsolidated Joint Ventures (Detail) $ in Thousands			12 Months Ended
	Nov. 03, 2017 Property	Jul. 12, 2017 Property	Dec. 31, 2017 USD ($) ft² Property
Income Statement Equity Method Investments [Line Items]
Number of properties | Property			23
Total GLA | ft²			4,233
Initial Value | $			$ 297,660
General Growth Properties, Inc. I [Member]
Income Statement Equity Method Investments [Line Items]
Seritage % Ownership			50.00%
Number of properties | Property		12	4
Total GLA | ft²			598
Initial Value | $			$ 37,570
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			1,187
Initial Value | $			$ 57,500
The Macerich Company [Member]
Income Statement Equity Method Investments [Line Items]
Seritage % Ownership			50.00%
Number of properties | Property			9
Total GLA | ft²			1,576
Initial Value | $			$ 150,000
Simon Property Group Inc [Member]
Income Statement Equity Method Investments [Line Items]
Seritage % Ownership			50.00%
Number of properties | Property	10		5
Total GLA | ft²			872
Initial Value | $			$ 52,590