Available increase in aggregate amount borrowed

No definition available.

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Namespace Prefix:	msm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Number of credit facilities

+ References

No definition available.

+ Details

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Data Type:	xbrli:positiveIntegerItemType
Balance Type:	na
Period Type:	duration

- 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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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(2))
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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Period of time between issuance and maturity of debt instrument, 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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Period Type:	duration

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
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+ Details

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

- Definition

The effective interest rate at the end of the reporting period.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of cash inflow from contractual arrangement with the lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
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-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3291-108585

+ Details

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

- Definition

Amount of cash outflow for payment of an obligation from a lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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-Section 45
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- Details

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Balance Type:
Period Type:

- Details

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Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=msm_CommittedCreditFacilityMember
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Balance Type:
Period Type:

- Details

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Period Type:

- Details

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Data Type:	na
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Period Type:

- Details

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Balance Type:
Period Type:

- Details

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Period Type:

Debt (Revolving Credit Facilities) (Narrative) (Details)	12 Months Ended
	Aug. 28, 2021 USD ($) agreement	Aug. 29, 2020 USD ($)	Aug. 31, 2019 USD ($)
Debt Instrument [Line Items]
Payments under revolving loans from credit facility	$ 399,200,000	$ 916,000,000	$ 451,000,000
Borrowings under credit facilities	583,500,000	1,012,200,000	$ 382,000,000
Amended Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity	$ 600,000,000
Maturity date	Aug. 24, 2026
Credit facility, expiration term	5 years
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Outstanding balance	$ 234,000,000	250,000,000
Committed Bank Facility [Member] \| Amended Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Available increase in amount borrowed	300,000,000
Letter of Credit [Member] \| Amended Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity	50,000,000
Outstanding balance	4,235,000	16,742,000
Uncommitted Bank Facilities [Member]
Debt Instrument [Line Items]
Outstanding balance	$ 201,500,000	$ 1,200,000
Amended Uncommitted Credit Facilities [Member]
Debt Instrument [Line Items]
Number of credit facilities \| agreement	2
Credit facility, maximum borrowing capacity	$ 208,000,000
Credit facility, expiration term	1 year
Weighted average rate under Credit Facility	1.11%	1.42%
Borrowings under credit facilities	$ 583,500,000
Repayment of loan facility	399,200,000
Outstanding balance	201,500,000
Current Portion Of Debt Including Obligations Under Finance Leases [Member] \| Amended Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Outstanding balance		$ 100,000,000
Current Portion Of Debt Including Obligations Under Finance Leases [Member] \| Uncommitted Bank Facilities [Member]
Debt Instrument [Line Items]
Outstanding balance		$ 1,200,000
Current Portion Of Debt Including Obligations Under Finance Leases [Member] \| Amended Uncommitted Credit Facilities [Member]
Debt Instrument [Line Items]
Outstanding balance	$ 201,500,000