Segment Information (Summary of Consolidated Net Sales and Earnings by Segment) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Consolidated net sales	$ 758,844	$ 548,249	$ 1,411,655	$ 1,018,397
Interest expense, net	(11,186)	(8,352)	(22,693)	(16,861)
Consolidated earnings before income taxes	90,168	48,647	151,683	86,134
Aerospace [Member]
Segment Reporting Information [Line Items]
Consolidated net sales	482,954		875,841
Industrial [Member]
Segment Reporting Information [Line Items]
Consolidated net sales	275,890		535,814
Operating Segments [Member] \| Aerospace [Member]
Segment Reporting Information [Line Items]
Consolidated net sales	482,954	386,343	875,841	692,248
Segment earnings (loss)	101,722	74,656	174,576	119,897
Operating Segments [Member] \| Industrial [Member]
Segment Reporting Information [Line Items]
Consolidated net sales	275,890	161,906	535,814	326,149
Segment earnings (loss)	27,128	10,687	56,297	30,468
Unallocated Corporate [Member]
Segment Reporting Information [Line Items]
Segment earnings (loss)	$ (27,496)	$ (28,344)	$ (56,497)	$ (47,370)

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

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