Retirement Plans (Reconciliation of Changes in Benefit Obligations, Plan Assets and Funded Status of Retirement Plans) (Details) - USD ($) $ in Thousands	4 Months Ended	12 Months Ended
	Jan. 19, 2020	Oct. 03, 2021	Sep. 27, 2020	Sep. 29, 2019
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at beginning of year		$ 365,510
Settlements	$ (122,300)
Fair value at end of year		409,708	$ 365,510
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Net actuarial (gain) loss		(44,134)	4,875	$ 62,377
Total recognized in OCI		(49,065)	(39,741)	58,460
Supplemental Employee Retirement Plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Obligation at beginning of year	79,893	78,971	79,893
Interest cost		2,169	2,499	3,080
Participant contributions		0	0
Actuarial (gain) loss		(672)	1,739
Benefits paid		(5,243)	(5,160)
Settlements		0	0
Other		0	0
Obligation at end of year		75,225	78,971	79,893
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at beginning of year	0	0	0
Actual return on plan assets		0	0
Participant contributions		0	0
Employer contributions		5,243	5,160
Benefits paid		(5,243)	(5,160)
Settlements		0	0
Other		0	0
Fair value at end of year		0	0	0
Unfunded status at end of year		(75,225)	(78,971)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Current liabilities		(5,216)	(5,223)
Noncurrent liabilities		(70,009)	(73,748)
Total liability recognized		(75,225)	(78,971)
Unamortized actuarial loss (gain), net		32,475	34,890
Unamortized prior service cost		53	72
Total		32,528	34,962
Net actuarial (gain) loss		(672)	1,739
Pension settlement costs		0	0
Amortization of actuarial (loss) gain		(1,743)	(1,652)
Amortization of prior service cost		(19)	(85)
Total recognized in OCI		(2,434)	2
Net periodic benefit (credit) cost and other losses		3,931	4,236	4,402
Total recognized in comprehensive income		1,497	4,238
Net actuarial loss (gain)		1,666
Prior service cost		19
Total		1,685
Postretirement Health Plans
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Obligation at beginning of year	25,632	20,965	25,632
Interest cost		563	807	997
Participant contributions		112	106
Actuarial (gain) loss		(3,525)	(4,391)
Benefits paid		(1,044)	(1,246)
Settlements		0	0
Other		91	57
Obligation at end of year		17,162	20,965	25,632
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at beginning of year	0	0	0
Actual return on plan assets		0	0
Participant contributions		112	106
Employer contributions		841	1,083
Benefits paid		(1,044)	(1,246)
Settlements		0	0
Other		91	57
Fair value at end of year		0	0	0
Unfunded status at end of year		(17,162)	(20,965)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Current liabilities		(1,115)	(1,243)
Noncurrent liabilities		(16,047)	(19,722)
Total liability recognized		(17,162)	(20,965)
Unamortized actuarial loss (gain), net		(7,359)	(4,174)
Unamortized prior service cost		0	0
Total		(7,359)	(4,174)
Net actuarial (gain) loss		(3,526)	(4,391)
Pension settlement costs		0	0
Amortization of actuarial (loss) gain		341	(18)
Amortization of prior service cost		0	0
Total recognized in OCI		(3,185)	(4,409)
Net periodic benefit (credit) cost and other losses		222	825	838
Total recognized in comprehensive income		(2,963)	(3,584)
Net actuarial loss (gain)		(640)
Prior service cost		0
Total		(640)
Qualified Pension Plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Obligation at beginning of year	521,931	412,573	521,931
Interest cost		12,558	13,377	19,825
Participant contributions		0	0
Actuarial (gain) loss		(785)	14,498
Benefits paid		(14,293)	(12,980)
Settlements		0	(124,253)
Other		0	0
Obligation at end of year		410,053	412,573	521,931
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at beginning of year	$ 476,194	365,510	476,194
Actual return on plan assets		58,491	26,549
Participant contributions		0	0
Employer contributions		0	0
Benefits paid		(14,293)	(12,980)
Settlements		0	(124,253)
Other		0	0
Fair value at end of year		409,708	365,510	476,194
Unfunded status at end of year		(345)	(47,063)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Current liabilities		0	0
Noncurrent liabilities		(345)	(47,063)
Total liability recognized		(345)	(47,063)
Unamortized actuarial loss (gain), net		108,922	152,370
Unamortized prior service cost		0	0
Total		108,922	152,370
Net actuarial (gain) loss		(39,936)	7,527
Pension settlement costs		0	(39,218)
Amortization of actuarial (loss) gain		(3,510)	(3,644)
Amortization of prior service cost		0	0
Total recognized in OCI		(43,446)	(35,335)
Net periodic benefit (credit) cost and other losses		(3,272)	36,661	$ (3,755)
Total recognized in comprehensive income		(46,718)	$ 1,326
Net actuarial loss (gain)		2,193
Prior service cost		0
Total		$ 2,193