Shareholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Jun. 30, 2020	May 30, 2020	Jun. 01, 2019	May 30, 2020	Jun. 01, 2019
Components Of Shareholders Equity [Line Items]
Treasury stock reissued to fund plan, shares		20,000	14,000	55,000	47,000
Subsequent Event [Member]
Components Of Shareholders Equity [Line Items]
Dividends payable per share	$ 0.75
Dividend payable date	Jul. 28, 2020
Dividends record date	Jul. 14, 2020
Dividend payable amount	$ 41,685
Class A Common Stock [Member]
Components Of Shareholders Equity [Line Items]
Common stock shares repurchased		500	500	44,000	316,000
Treasury stock repurchased, and treasury stock repurchased and retired, shares					1,054,000
Treasury stock repurchased, and treasury stock repurchased and retired, amount			$ 39		$ 84,464
Number of shares authorized for repurchase		1,157,000		1,157,000
Treasury Stock [Member] | Class A Common Stock [Member]
Components Of Shareholders Equity [Line Items]
Purchase of treasury stock		$ 28	$ 39	$ 3,236	$ 24,137