Consolidated Statements of Earnings - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Net sales	$ 2,495,665	$ 2,900,197	$ 2,325,873
Costs and expenses:
Cost of goods sold	1,855,422	2,192,654	1,722,802
Selling, general and administrative expenses	217,710	211,205	193,736
Research and development costs	133,134	159,107	148,279
Impairment of assets sold	37,902
Restructuring charges	22,216		17,013
Gain on cross-currency interest rate swaps, net	(30,481)
Interest expense	35,811	44,001	40,465
Interest income	(1,764)	(1,413)	(1,674)
Other (income) expense, net	(56,166)	(25,969)	(14,326)
Total costs and expenses	2,213,784	2,579,585	2,106,295
Earnings before income taxes	281,881	320,612	219,578
Income tax expense	41,486	61,010	39,200
Net earnings	$ 240,395	$ 259,602	$ 180,378
Earnings per share:
Basic earnings per share	$ 3.86	$ 4.19	$ 2.93
Diluted earnings per share	$ 3.74	$ 4.02	$ 2.82
Weighted Average Common Shares Outstanding:
Basic	62,267	61,950	61,493
Diluted	64,209	64,498	63,876