Document And Entity Information - shares	6 Months Ended
	Feb. 29, 2020	Mar. 16, 2020
Class of Stock [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Feb. 29, 2020
Document Transition Report	false
Entity File Number	1-14130
Entity Registrant Name	MSC INDUSTRIAL DIRECT CO., INC.
Entity Incorporation, State or Country Code	NY
Entity Tax Identification Number	11-3289165
Entity Address, Address Line One	75 Maxess Road
Entity Address, City or Town	Melville
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	11747
City Area Code	516
Local Phone Number	812-2000
Title of 12(b) Security	Class A Common Stock, par value $.001
Trading Symbol	MSM
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Central Index Key	0001003078
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--08-29
Amendment Flag	false
Class A Common Stock [Member]
Class of Stock [Line Items]
Entity Common Stock, Shares Outstanding		45,426,994
Class B Common Stock [Member]
Class of Stock [Line Items]
Entity Common Stock, Shares Outstanding		10,129,856