Note 11 Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Oct. 01, 2016
Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	3,521	6	480
Net income (loss)	$ (95,533)	$ 138,833	$ 187,838
Potentially dilutive securities	3,000
Weighted average shares used in computing per share amount:
Weighted average common shares outstanding	69,833	74,481	75,094
Effect of dilutive stock options and restricted stock units	0	3,647	3,693
Denominator for diluted earnings per share	69,833	78,128	78,787
Net income (loss) per share:
Basic	$ (1.37)	$ 1.86	$ 2.50
Diluted	$ (1.37)	$ 1.78	$ 2.38
Employee stock options
Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	2,061	0	477
Restricted stock units
Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1,460	6	3