Condensed Consolidated Statement Of Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Class A Common Stock [Member] Common Stock [Member]	Class A Common Stock [Member] Retained Earnings [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)
Exchange of Class B common stock for Class A common stock, value	1			(1)
Associate Incentive Plans							25,445			1,125
Repurchases of common stock, Value										(21,728)			$ (21,728)
Cash dividends on common stock		$ (47,687)			$ (12,186)
Dividend equivalents declared, net of cancellations								(395)
Foreign currency translation adjustment									(816)				(816)
Net Income								177,137					177,137
Balance, Value at Mar. 03, 2018	55			11			652,440	1,285,681	(18,079)	(574,073)	$ 1,346,035		1,346,035
Dividends declared per common share			$ 1.06			$ 1.06
Balance, Value at Dec. 02, 2017	54			11			633,944	1,201,128	(18,106)	(557,000)
Exchange of Class B common stock for Class A common stock, value	1
Associate Incentive Plans							18,496			637
Repurchases of common stock, Value										(17,710)			(17,710)
Cash dividends on common stock		(26,228)			(6,558)
Dividend equivalents declared, net of cancellations								(213)
Foreign currency translation adjustment									27				27
Net Income								117,552					117,552
Balance, Value at Mar. 03, 2018	55			11			652,440	1,285,681	(18,079)	(574,073)	1,346,035		1,346,035
Dividends declared per common share			$ 0.58			0.58
Balance, Value at Sep. 01, 2018	55			10			657,749	1,325,822	(19,634)	(576,748)			1,387,254
Associate Incentive Plans							24,185			1,243
Repurchases of common stock, Shares			315
Repurchases of common stock, Value			$ (24,098)							(24,098)
Repurchase and retirement of common stock, Value	(1)						(11,887)	(48,439)
Cash dividends on common stock		(56,707)			(12,844)
Dividend equivalents declared, net of cancellations								(516)
Issuance of Noncontrolling Interest in MSC Mexico												$ 4,637
Capital contributions												1,022
Foreign currency translation adjustment									(603)			(63)	(666)
Net Income								142,656				6	142,662
Balance, Value at Mar. 02, 2019	54			10			670,047	1,349,972	(20,237)	(599,603)	1,400,243	5,602	1,405,845
Dividends declared per common share			$ 1.26			1.26
Balance, Value at Dec. 01, 2018	54			10			660,185	1,316,489	(20,975)	(579,451)
Associate Incentive Plans							9,862			746
Repurchases of common stock, Shares			275
Repurchases of common stock, Value			$ (20,898)							(20,898)
Cash dividends on common stock		$ (28,271)			$ (6,422)
Dividend equivalents declared, net of cancellations								(248)
Issuance of Noncontrolling Interest in MSC Mexico												4,637
Capital contributions												1,022
Foreign currency translation adjustment									738			(63)	675
Net Income								68,424				6	68,430
Balance, Value at Mar. 02, 2019	$ 54			$ 10			$ 670,047	$ 1,349,972	$ (20,237)	$ (599,603)	$ 1,400,243	$ 5,602	$ 1,405,845
Dividends declared per common share			$ 0.63			$ 0.63