Consolidated Statements Of Shareholders' Equity - USD ($) $ in Thousands	Class A Common Stock [Member] Common Stock [Member]	Class A Common Stock [Member] Additional Paid-In-Capital [Member]	Class A Common Stock [Member] Retained Earnings [Member]	Class A Common Stock [Member] Treasury Stock [Member]	Class A Common Stock [Member]	Class B Common Stock [Member] Common Stock [Member]	Class B Common Stock [Member] Retained Earnings [Member]	Class B Common Stock [Member]	Additional Paid-In-Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Treasury Stock [Member]	Total Shareholders' Equity Attributable to MSC Industrial [Member]	Noncontrolling Interest [Member]	Total
Balance, Value at Sep. 02, 2017	$ 54					$ 12			$ 626,995	$ 1,168,812	$ (17,263)	$ (553,470)
Foreign Currency Translation Adjustment											(2,371)				$ (2,371)
Net Income										329,223					329,223
Associate Incentive Plans									41,706			2,154
Repurchase and retirement of Class A common stock, Value	(1)	$ (10,952)	$ (45,984)
Repurchase of Class A common stock, Value				$ (25,432)
Exchange of Class B common stock for Class A common stock, value	2					(2)
Cash dividends declared on common stock			(101,000)				$ (24,430)
Dividend equivalents declared, net of cancellations										(799)
Balance, Value at Sep. 01, 2018	55					10			657,749	1,325,822	(19,634)	(576,748)	$ 1,387,254		1,387,254
Dividends declared per common share					$ 2.22			$ 2.22
Issuance of Noncontrolling Interest in MSC Mexico														$ 4,637
Capital Contributions														1,022
Foreign Currency Translation Adjustment											(3,142)			(262)	(3,404)
Net Income										288,865				(68)	288,865
Associate Incentive Plans									34,138			2,813
Repurchase and retirement of Class A common stock, Value	(1)	$ (11,887)	(48,439)												(493,612)
Repurchase of Class A common stock, Value				(24,284)											(84,611)
Retirement of treasury stock, Value	(8)								(20,774)	(472,830)		493,612
Cash dividends declared on common stock			(118,798)				(26,911)
Dividend equivalents declared, net of cancellations										(1,058)
Balance, Value at Aug. 31, 2019	46					10			659,226	946,651	(22,776)	(104,607)	1,478,550	5,329	1,483,879
Dividends declared per common share					2.64			2.64
Foreign Currency Translation Adjustment											1,358			(342)	1,016
Net Income										251,117				641	251,117
Associate Incentive Plans	1								31,513			4,103
Repurchase of Class A common stock, Value				$ (3,444)
Cash dividends declared on common stock			$ (363,242)				$ (80,929)
Dividend equivalents declared, net of cancellations										(4,082)
Balance, Value at Aug. 29, 2020	$ 47					$ 10			$ 690,739	$ 749,515	$ (21,418)	$ (103,948)	$ 1,314,945	$ 5,628	$ 1,320,573
Dividends declared per common share					$ 8.00			$ 8.00