Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands		Total	Common Stock	Additional Paid-In Capital	Treasury Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Sep. 30, 2017			33,464,000
Beginning balance at Sep. 30, 2017		$ 1,025,939	$ 519	$ 555,297	$ (574,104)	$ 1,049,206	$ (4,979)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(98,493)				(98,493)
Other comprehensive income (loss)		3,681					3,681
Treasury shares purchased (in shares)			(158,000)
Treasury shares purchased		(9,547)			(9,547)
Share-based compensation expense		3,896		3,896
Exercise of stock options, including tax benefits (in shares)			301,000
Exercise of stock options, including tax benefits		8,372	$ 3	8,369
Ending balance (in shares) at Dec. 30, 2017			33,607,000
Ending balance at Dec. 30, 2017		933,848	$ 522	567,562	(583,651)	950,713	(1,298)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment for adoption of new accounting principle in pronouncement	[1]	$ 7,815				7,815
Beginning balance (in shares) at Sep. 29, 2018		31,838,000	31,838,000
Beginning balance at Sep. 29, 2018		$ 921,143	$ 526	581,488	(711,138)	1,062,246	(11,979)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		22,226				22,226
Other comprehensive income (loss)		(1,493)					(1,493)
Treasury shares purchased (in shares)			(870,000)
Treasury shares purchased		(50,051)			(50,051)
Share-based compensation expense		4,753		4,753
Exercise of stock options, including tax benefits (in shares)			24,000
Exercise of stock options, including tax benefits		$ 770		770
Ending balance (in shares) at Dec. 29, 2018		30,992,000	30,992,000
Ending balance at Dec. 29, 2018		$ 905,163	$ 526	$ 587,011	$ (761,189)	$ 1,092,287	$ (13,472)

[1] See Note 1, "Basis of Presentation", for a discussion of recently adopted accounting pronouncements.