Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Sep. 27, 2020	Sep. 29, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net earnings	$ 89,764	$ 94,437	$ 121,371
Net change in fair value of derivatives	0	(23,625)	18,769
Loss reclassified from accumulated OCI into net earnings	0	24,328	3,455
Cash flow hedges	0	703	22,224
Tax effect	0	(3,165)	(5,725)
Cash flow hedges, net of tax	0	(2,462)	16,499
Actuarial gains (losses) arising during the period	(4,875)	(62,377)	31,478
Actuarial losses and prior service cost reclassified to earnings	44,616	3,917	4,988
Unrecognized periodic benefit costs, before tax	39,741	(58,460)	36,466
Tax effect	(10,340)	15,176	(9,544)
Unrecognized periodic benefit costs, net of tax	29,401	(43,284)	26,922
Foreign currency translation adjustments	0	0	6
Tax effect	0	0	(2)
Derecognition of foreign currency translation adjustments due to sale	0	0	76
Other comprehensive income (loss), foreign currency transaction and translation gain (loss) arising during period, net of tax	0	0	80
Other comprehensive income (loss), net of taxes	29,401	(45,746)	43,501
Comprehensive income	$ 119,165	$ 48,691	$ 164,872