CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Dec. 30, 2017	Dec. 24, 2016
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 37,168	$ 34,489
Other comprehensive income:
Net unrealized (losses) on cash flow hedges	0	(5)
Reclassification of realized losses on cash flow hedges into earnings	0	200
Amortization of net actuarial losses and prior service credits into earnings	757	1,203
Other comprehensive income	757	1,398
Total comprehensive income	$ 37,925	$ 35,887