Consolidated Statements of Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 30, 2019	Mar. 31, 2018	Mar. 30, 2019	Mar. 31, 2018
Income Statement [Abstract]
Net sales	$ 789,051	$ 698,651	$ 1,554,595	$ 1,375,945
Cost of sales	718,415	645,699	1,411,576	1,259,470
Gross profit	70,636	52,952	143,019	116,475
Selling and administrative expenses	37,462	35,637	72,894	67,603
Operating income	33,174	17,315	70,125	48,872
Other income (expense):
Interest expense	(3,145)	(3,547)	(5,394)	(7,272)
Interest income	440	1,426	965	2,981
Miscellaneous, net	(1,773)	(477)	(2,885)	(823)
Income before income taxes	28,696	14,717	62,811	43,758
Income tax expense	3,938	2,427	15,827	129,961
Net income (loss)	$ 24,758	$ 12,290	$ 46,984	$ (86,203)
Earnings (loss) per share:
Basic (in dollars per share)	$ 0.81	$ 0.37	$ 1.52	$ (2.57)
Diluted (in dollars per share)	$ 0.79	$ 0.36	$ 1.48	$ (2.57)
Weighted average shares outstanding:
Basic (in shares)	30,603	33,538	31,003	33,552
Diluted (in shares)	31,385	34,387	31,836	33,552
Other comprehensive income:
Derivative instrument fair value adjustment	$ 1,984	$ 1,229	$ 2,362	$ 2,768
Foreign currency translation adjustments	515	4,773	(1,356)	6,915
Other comprehensive income	2,499	6,002	1,006	9,683
Total comprehensive income (loss)	$ 27,257	$ 18,292	$ 47,990	$ (76,520)