Document And Entity Information (USD $)	12 Months Ended
	Sep. 01, 2012	Feb. 25, 2012	Oct. 24, 2012 Class A Common Stock [Member]	Oct. 24, 2012 Class B Common Stock [Member]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Sep. 01, 2012
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	FY
Entity Registrant Name	MSC INDUSTRIAL DIRECT CO INC
Entity Central Index Key	0001003078
Current Fiscal Year End Date	--09-01
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding			47,241,983	15,510,294
Entity Public Float		$ 3,695,330,431
Entity Current Reporting Status	Yes
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No