Consolidated Condensed Statements of Shareholders' Equity Statement - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock At Cost	Stock Employee Compensation Trust (SECT)	Supplemental Retirement Plan (SERP) Trust	Accumulated Other Comprehensive Loss	Class A Common Stock	Class A Common Stock Treasury Stock At Cost	Class A Common Stock Stock Employee Compensation Trust (SECT)	Class B Common Stock	Class B Common Stock Treasury Stock At Cost	Class B Common Stock Stock Employee Compensation Trust (SECT)	Class B Common Stock Supplemental Retirement Plan (SERP) Trust
Beginning of period at Sep. 29, 2018		$ 51,280	$ 502,257	$ 1,974,125	$ (738,494)	$ (118,449)	$ (72,941)	$ (372,792)
Increase (Decrease) in Stockholders' Equity
Issuance of shares			(116)		6,154
Equity-based compensation expense			5,130
Adjustment to market - SECT, SERP and other			18,691
Net earnings (loss)	$ 129,993			129,993
Dividends				(26,156)
Adoption of ASC 606 | ASC 606				14,923
Class A and B shares purchased					(17,986)
Issuance of shares - SECT						18,236	4,293
Purchase of shares - SECT	(13,327)					(13,327)
Adjustment to market						(10,588)	(8,103)
Other comprehensive income (loss)	9,527							9,527
End of period at Jun. 29, 2019	1,355,657	51,280	525,962	2,092,885	(750,326)	(124,128)	(76,751)	(363,265)
Beginning of period - Common Stock at Sep. 29, 2018									43,784,489			7,495,224
Increase (Decrease) in Stockholders' Equity
Conversion of Class B to Class A									4,558			(4,558)
End of period - Common Stock at Jun. 29, 2019									43,789,047			7,490,666
Beginning of period, Shares at Sep. 29, 2018										(10,872,575)	(425,148)		(3,323,996)	(983,772)	(876,170)
Increase (Decrease) in Stockholders' Equity
Class A and B shares issued related to equity compensation, shares										103,232			104,465
Class A and B shares purchased, shares										(95,498)			(125,583)
Issuance of shares - SECT														227,816
Purchase of shares - SECT														(151,793)
End of period, Shares at Jun. 29, 2019										(10,864,841)	(425,148)		(3,345,114)	(907,749)	(826,170)
Beginning of period at Mar. 30, 2019		51,280	510,538	2,055,446	(749,845)	(109,506)	(75,079)	(368,392)
Increase (Decrease) in Stockholders' Equity
Issuance of shares			(1,186)		1,186
Equity-based compensation expense			1,439
Adjustment to market - SECT, SERP and other			15,171
Net earnings (loss)	46,165			46,165
Dividends				(8,726)
Adoption of ASC 606 | ASC 606				0
Class A and B shares purchased					(1,667)
Issuance of shares - SECT						557	4,293
Purchase of shares - SECT						(5,973)
Adjustment to market						(9,206)	(5,965)
Other comprehensive income (loss)	5,127							5,127
End of period at Jun. 29, 2019	1,355,657	51,280	525,962	2,092,885	(750,326)	(124,128)	(76,751)	(363,265)
Beginning of period - Common Stock at Mar. 30, 2019									43,785,435			7,494,278
Increase (Decrease) in Stockholders' Equity
Conversion of Class B to Class A									3,612			(3,612)
End of period - Common Stock at Jun. 29, 2019									43,789,047			7,490,666
Beginning of period, Shares at Mar. 30, 2019										(10,882,780)	(425,148)		(3,347,250)	(846,527)	(876,170)
Increase (Decrease) in Stockholders' Equity
Class A and B shares issued related to equity compensation, shares										31,369			6,136
Class A and B shares purchased, shares										(13,430)			(4,000)
Issuance of shares - SECT														6,490
Purchase of shares - SECT														(67,712)
End of period, Shares at Jun. 29, 2019										(10,864,841)	(425,148)		(3,345,114)	(907,749)	(826,170)
Beginning of period at Sep. 28, 2019	1,322,481	51,280	510,546	2,128,739	(769,569)	(111,492)	(71,546)	(415,477)
Increase (Decrease) in Stockholders' Equity
Issuance of shares			3,767		4,448
Equity-based compensation expense			4,661
Adjustment to market - SECT, SERP and other			(56,688)
Net earnings (loss)	87,182			87,182
Dividends				(17,049)
Adoption of ASC 606 | ASC 606				0
Class A and B shares purchased					(191,961)
Issuance of shares - SECT						21,129	0
Purchase of shares - SECT	(6,241)					(6,241)
Adjustment to market						34,797	21,891
Other comprehensive income (loss)	17,344							17,344
End of period at Jun. 27, 2020	1,245,761	51,280	462,286	2,198,872	(957,082)	(61,807)	(49,655)	(398,133)
Beginning of period - Common Stock at Sep. 28, 2019									43,794,935			7,484,778
Increase (Decrease) in Stockholders' Equity
Conversion of Class B to Class A									4,294			(4,294)
End of period - Common Stock at Jun. 27, 2020									43,799,229			7,480,484
Beginning of period, Shares at Sep. 28, 2019										(11,101,512)	(425,148)		(3,345,489)	(886,300)	(826,170)
Increase (Decrease) in Stockholders' Equity
Class A and B shares issued related to equity compensation, shares										17,599			138,784
Class A and B shares purchased, shares										(2,286,697)			(138,172)
Issuance of shares - SECT														271,577
Purchase of shares - SECT														(70,177)
End of period, Shares at Jun. 27, 2020										(13,370,610)	(425,148)		(3,344,877)	(684,900)	(826,170)
Beginning of period at Mar. 28, 2020		51,280	449,720	2,211,462	(957,082)	(60,386)	(42,672)	(406,644)
Increase (Decrease) in Stockholders' Equity
Issuance of shares			0		0
Equity-based compensation expense			1,390
Adjustment to market - SECT, SERP and other			11,176
Net earnings (loss)	(12,590)			(12,590)
Dividends				0
Adoption of ASC 606 | ASC 606				0
Class A and B shares purchased					0
Issuance of shares - SECT						2,804	0
Purchase of shares - SECT						(32)
Adjustment to market						(4,193)	(6,983)
Other comprehensive income (loss)	8,511							8,511
End of period at Jun. 27, 2020	$ 1,245,761	$ 51,280	$ 462,286	$ 2,198,872	$ (957,082)	$ (61,807)	$ (49,655)	$ (398,133)
Beginning of period - Common Stock at Mar. 28, 2020									43,799,229			7,480,484
Increase (Decrease) in Stockholders' Equity
Conversion of Class B to Class A									0			0
End of period - Common Stock at Jun. 27, 2020									43,799,229			7,480,484
Beginning of period, Shares at Mar. 28, 2020										(13,370,610)	(425,148)		(3,344,877)	(734,606)	(826,170)
Increase (Decrease) in Stockholders' Equity
Class A and B shares issued related to equity compensation, shares										0			0
Class A and B shares purchased, shares										0			0
Issuance of shares - SECT														50,321
Purchase of shares - SECT														(615)
End of period, Shares at Jun. 27, 2020										(13,370,610)	(425,148)		(3,344,877)	(684,900)	(826,170)