Document And Entity Information	9 Months Ended
	May 26, 2012	Jun. 22, 2012 Class A Common Stock [Member]	Jun. 22, 2012 Class B Common Stock [Member]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	May 26, 2012
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q3
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		46,719,059	16,015,474