CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 27, 2021	Mar. 28, 2020	Mar. 27, 2021	Mar. 28, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 127,216	$ 77,361	$ 165,193	$ 117,524
Amortization of net actuarial losses and prior service credits into earnings	593	541	1,186	1,082
Recognition in earnings of net actuarial loss for pension settlement	570	0	570	0
Other comprehensive income	1,163	541	1,756	1,082
Total comprehensive income	$ 128,379	$ 77,902	$ 166,949	$ 118,606