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Share Based Compensation - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Jul. 07, 2015
Time Based Restricted Shares and Share Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			3 years
Restricted Share [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs	$ 5.3	$ 3.2	$ 5.3	$ 3.2
Unrecognized compensation costs, weighted average expected recognition period			2 years	2 years 1 month 6 days
Restricted Share [Member] \| General and Administrative Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense recognized	$ 1.0	$ 0.4	$ 2.1	$ 1.5
Seritage Growth Properties 2015 Share Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock reserved for issuance					3,250,000