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Concentration of Credit Risk - Additional Information (Detail) | 12 Months Ended
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Dec. 30, 2017 USD ($) Retailer
Concentration Of Credit Risk [Line Items] |
Number of independent retailer for unearned advanced amount | Retailer | 1
Reserve established for unearned portion of funds advanced | $ 4,900,000
Percent of unearned advanced amount to total assets | 2.00%
Present value of potential obligation for sub-lease | $ 6,400,000
Assigned sublease obligation | 13,800,000
Bank debt guaranteed | 1,500,000
Payments required under guarantee | 0
Loss incurred under guarantee | $ 0
Minimum [Member] |
Concentration Of Credit Risk [Line Items] |
Loan repayable period | 5 years
Estimated loss contingency, in excess of amount currently reserved | $ 0
Maximum [Member] |
Concentration Of Credit Risk [Line Items] |
Loan repayable period | 10 years
Estimated loss contingency, in excess of amount currently reserved | $ 25,000,000

X
- Definition Assigned sublease obligation. + References No definition available. + Details
Name: | sptn_AssignedSubleaseObligation
Namespace Prefix: | sptn_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Concentration of credit risk. + References No definition available. + Details
Name: | sptn_ConcentrationOfCreditRiskLineItems
Namespace Prefix: | sptn_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Loan repayable period. + References No definition available. + Details
Name: | sptn_LoanRepayablePeriod
Namespace Prefix: | sptn_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Loss incurred under guarantee. + References No definition available. + Details
Name: | sptn_LossIncurredUnderGuarantee
Namespace Prefix: | sptn_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Number of independent retailer unearned advanced amount. + References No definition available. + Details
Name: | sptn_NumberOfIndependentRetailerUnearnedAdvancedAmount
Namespace Prefix: | sptn_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Payments required under guarantee. + References No definition available. + Details
Name: | sptn_PaymentsRequiredUnderGuarantee
Namespace Prefix: | sptn_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Percent of unearned advanced amount to net assets. + References No definition available. + Details
Name: | sptn_PercentOfUnearnedAdvancedAmountToNetAssets
Namespace Prefix: | sptn_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Present value of maximum potential sublease obligation. + References No definition available. + Details
Name: | sptn_PresentValueOfMaximumPotentialSubleaseObligation
Namespace Prefix: | sptn_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Reserve for unearned portion of funds advanced. + References No definition available. + Details
Name: | sptn_ReserveForUnearnedPortionOfFundsAdvanced
Namespace Prefix: | sptn_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The current carrying amount of the liability for the freestanding or embedded guarantor's obligations under the guarantee or each group of similar guarantees. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 460 -SubTopic 10 -Section 50 -Paragraph 4 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=82913245&loc=d3e12069-110248 + Details
Name: | us-gaap_GuaranteeObligationsCurrentCarryingValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of receivable related to a loss contingency accrual. For example, an insurance recovery receivable. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 460 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=82913245&loc=d3e12053-110248 + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
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Namespace Prefix: |
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Balance Type: |
Period Type: |

X
- Details
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Namespace Prefix: |
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Balance Type: |
Period Type: |