CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Sep. 24, 2016	Sep. 26, 2015	Sep. 27, 2014
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 14,440	$ 84,352	$ 94,509
Other comprehensive income:
Net unrealized gains (losses) on cash flow hedges	6	(1,159)	(518)
Reclassification of realized losses on cash flow hedges into earnings	1,100	1,388	1,406
Amortization of net actuarial losses and prior service credits into earnings and net change in funded status of benefit plans	(55)	(5,207)	560
Recognition in earnings of net actuarial loss for pension settlement	2,000	2,000	0
Other comprehensive income (loss)	3,051	(2,978)	1,448
Total comprehensive income	$ 17,491	$ 81,374	$ 95,957