Earnings per Share (EPS) and Common Stock (Earnings per Share Basic and Diluted) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018
Earnings Per Share and Common Stock
Net income (loss)	$ (14,758)	$ 16,997	$ (37,286)	$ 38,796
Weighted average shares outstanding—Basic (in shares)	116,133	115,774	117,636	115,915
Dilutive effect of employee stock options, restricted shares and restricted stock units (in shares)	0	1,726	0	1,772
Weighted average shares outstanding—Diluted (in shares)	116,133	117,500	117,636	117,687
Earnings per share—Basic (in USD per share)	$ (0.13)	$ 0.15	$ (0.32)	$ 0.33
Earnings per share—Diluted (in USD per share)	$ (0.13)	$ 0.14	$ (0.32)	$ 0.33