Cash Equivalents Fair Value Disclosure

No definition available.

Name:	msm_CashEquivalentsFairValueDisclosure
Namespace Prefix:	msm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of addition (reduction) to the amount at which an asset could be incurred (settled) in a current transaction between willing parties.

+ References

No definition available.

+ Details

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

- Definition

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This item represents the difference between the gross realized gains and losses realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

+ References

No definition available.

+ Details

Name:	us-gaap_AvailableforsaleSecuritiesGrossRealizedGainLossExcludingOtherThanTemporaryImpairments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- 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

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
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- Definition

Amount of addition (reduction) to the amount at which a liability could be incurred (settled) in a current transaction between willing parties.

+ References

No definition available.

+ Details

Name:	us-gaap_LiabilitiesFairValueAdjustment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

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Namespace Prefix:
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Balance Type:
Period Type:

Fair Value (Details) - USD ($)	12 Months Ended
Fair Value (Details) - USD ($)	Aug. 29, 2020	Aug. 31, 2019	Aug. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents, fair value	$ 0	$ 0
Fair value remeasurement of non-financial assets on non-recurring basis	0
Fair value remeasurement of non-financial liabilities on non-recurring basis	$ 0
Corporate Bond Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Taxable bonds			$ 27,025,000
Gains and losses on securities		$ 0