CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Sep. 28, 2019	Sep. 29, 2018	Sep. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 68,632	$ 76,534	$ 37,995
Other comprehensive (loss) income:
Net unrealized (loss) on cash flow hedges			(10)
Reclassification of realized losses on cash flow hedges into earnings			215
Amortization of net actuarial losses and prior service credits into earnings and net change in funded status of benefit plans	(1,516)	4,142	10,715
Recognition in earnings of net actuarial loss for pension settlement	0	0	6,100
Other comprehensive (loss) income	(1,516)	4,142	17,020
Total comprehensive income	$ 67,116	$ 80,676	$ 55,015