Net Income Per Share (Computation Of Basic And Diluted Net Income Per Common Share Under Treasury Stock Method) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Aug. 28, 2021	Aug. 29, 2020	Aug. 31, 2019
Net Income Per Share [Abstract]
Net income attributable to MSC Industrial as reported	$ 216,907	$ 251,117	$ 288,865
Less: Distributed net income available to participating securities			(45)
Less: Undistributed net income available to participating securities			(75)
Undistributed and distributed net income available to common shareholders	216,907	251,117	288,745
Add: Undistributed net income allocated to participating securities			75
Less: Undistributed net income reallocated to participating securities			(75)
Undistributed and distributed net income available to common shareholders	$ 216,907	$ 251,117	$ 288,745
Weighted-average shares outstanding for basic net income per share	55,737	55,472	55,245
Effect of dilutive securities	356	171	263
Weighted-average shares outstanding for diluted net income per share	56,093	55,643	55,508
Basic	$ 3.89	$ 4.53	$ 5.23
Diluted	$ 3.87	$ 4.51	$ 5.20
Potentially dilutive securities	314	1,393	1,080