Earnings per Share - Reconciliation of Net Income (Loss) and Number of Common Shares Used in Computations of Basic Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Numerator - Basic and Diluted
Net loss	$ (154,911)	$ (120,097)	$ (38,985)
Net loss attributable to non-controlling interests		46,152	10,836
Preferred dividends	(4,900)	(4,900)	(4,900)
Net loss attributable to Seritage common shareholders	$ (159,811)	$ (78,845)	$ (33,049)
Denominator - Basic and Diluted
Weighted average Class A common shares outstanding	56,151	49,729	42,393
Weighted average Class A common shares outstanding - Diluted	56,151	49,729	42,393
Net loss per share attributable to Class A common shareholders - Basic	$ (2.85)	$ (1.59)	$ (0.78)
Net loss per share attributable to Class A common shareholders - Diluted	$ (2.85)	$ (1.59)	$ (0.78)
Class A Common Shares [Member]
Denominator - Basic and Diluted
Weighted average Class A common shares outstanding	56,151	49,729	42,393