Derivative term of contract maturity ending year.

No definition available.

Name:	sfm_DerivativeTermOfContractMaturityEndingYear
Namespace Prefix:	sfm_
Data Type:	xbrli:stringItemType
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Period Type:	duration

- Definition

Derivative term of contract maturity starting year.

+ References

No definition available.

+ Details

Name:	sfm_DerivativeTermOfContractMaturityStartingYear
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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of swaps outstanding.

+ References

No definition available.

+ Details

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Namespace Prefix:	sfm_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI https://asc.fasb.org/extlink&oid=125515794&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=125515794&loc=SL5579245-113959

+ Details

Name:	us-gaap_DerivativeNotionalAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of derivative instruments of a particular group held by the entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=125515794&loc=SL5579245-113959

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI https://asc.fasb.org/extlink&oid=125515794&loc=SL5580258-113959

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Period the derivative contract is outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_ForwardContractsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Derivative Financial Instruments - Additional Information (Detail) - Forward Contract [Member] $ in Millions	1 Months Ended
	Dec. 31, 2017 USD ($) Hedge	Apr. 02, 2023 Swap	Jan. 01, 2023 Swap
Derivative [Line Items]
Derivative, number of cash flow hedges \| Hedge	5
Number of outstanding swaps \| Swap		0	0
Cash Flow Hedges [Member]
Derivative [Line Items]
Derivative, notional amount of outstanding swaps \| $	$ 250.0
Derivative, cash flow swaps length period	1 year
Cash flow swaps mature annually, starting year	2018
Cash flow swaps mature annually, ending year	2022