Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Name:	us-gaap_GoodwillImpairmentLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Significant Accounting Policies - Goodwill and Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Dec. 31, 2017	Oct. 07, 2018
Signature brands
Goodwill and Intangible Assets
Weighted average amortization period (in years)		20 years
Leasehold interests
Goodwill and Intangible Assets
Weighted average amortization period (in years)		24 years
Smart & Final
Goodwill and Intangible Assets
Goodwill impairment charge	$ 180.0