Shareholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended	3 Months Ended		9 Months Ended
	Jun. 29, 2021	Jun. 30, 2021	May 29, 2021	May 30, 2020	May 29, 2021	May 30, 2020	Jan. 09, 2018
Components Of Shareholders Equity [Line Items]
Treasury stock reissued to fund plan, shares			13,000	20,000	44,000	55,000
Cash dividends paid per common share					$ 5.75
Cash dividends paid					$ 321,058
Subsequent Event [Member]
Components Of Shareholders Equity [Line Items]
Repurchase and retirement of common stock, Shares		229,000
Repurchase and retirement of common stock, Value		$ 20,373
Subsequent Event [Member] | Maximum [Member]
Components Of Shareholders Equity [Line Items]
Number of shares authorized for repurchase	5,000,000
Regular Dividends [Member]
Components Of Shareholders Equity [Line Items]
Cash dividends paid per common share					$ 2.25	$ 2.25
Cash dividends paid					$ 125,707	$ 124,851
Regular Dividends [Member] | Subsequent Event [Member]
Components Of Shareholders Equity [Line Items]
Dividends declared date	Jun. 29, 2021
Dividends payable per share	$ 0.75
Dividend payable date	Jul. 27, 2021
Dividends record date	Jul. 13, 2021
Dividend payable amount	$ 41,735
Special Dividends [Member]
Components Of Shareholders Equity [Line Items]
Cash dividends paid per common share					$ 3.50	$ 5.00
Cash dividends paid					$ 195,351	$ 277,634
MSC Stock Repurchase Plan [Member]
Components Of Shareholders Equity [Line Items]
Number of shares authorized for repurchase							2,000,000
Maximum number of shares that can be repurchased			650,000		650,000
Class A Common Stock [Member]
Components Of Shareholders Equity [Line Items]
Common stock shares repurchased				500		44,000
Repurchase and retirement of common stock, Shares			507,000		507,000
Purchase of treasury stock				$ 28		$ 3,236
Shares repurchased by the company for associates' tax withholding liability associated with share-based compensation			1,000		51,000
Treasury Stock [Member]
Components Of Shareholders Equity [Line Items]
Treasury stock repurchased, and treasury stock repurchased and retired, shares			508,000		558,000
Treasury stock repurchased, and treasury stock repurchased and retired, amount			$ 47,181		$ 50,700
Treasury Stock [Member] | Class A Common Stock [Member]
Components Of Shareholders Equity [Line Items]
Purchase of treasury stock			$ 88	$ 28	$ 3,607	$ 3,236