Note 11 Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017
Weighted average shares used in computing per share amount:
Net income (loss)	$ 24,632	$ 31,717	$ (130,278)	$ 76,581
Weighted average common shares outstanding	70,441	74,761	71,096	74,156
Effect of dilutive stock options and restricted stock units	3,141	3,103	0	3,375
Denominator for diluted earnings per share	73,582	77,864	71,096	77,531
Net income (loss) per share:
Basic	$ 0.35	$ 0.42	$ (1.83)	$ 1.03
Diluted	$ 0.33	$ 0.41	$ (1.83)	$ 0.99
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount			3,500