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. 30, 2018	Jul. 01, 2017	Jun. 30, 2018	Jul. 01, 2017
Earnings Per Share and Common Stock
Net income (loss)	$ 16,997	$ (951)	$ 38,796	$ (11,196)
Weighted average shares outstanding—Basic (in shares)	115,774	115,615	115,915	115,511
Dilutive effect of employee stock options, restricted shares and restricted stock units (in shares)	1,726	0	1,772	0
Weighted average shares outstanding—Diluted (in shares)	117,500	115,615	117,687	115,511
Earnings(loss) per share—Basic (in USD per share)	$ 0.15	$ (0.01)	$ 0.33	$ (0.10)
Earnings(loss) per share—Diluted (in USD per share)	$ 0.14	$ (0.01)	$ 0.33	$ (0.10)