DISCONTINUED OPERATIONS - Income Statement Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income from discontinued operations before taxes	$ 113,457	$ 2,180	$ 117,777	$ 3,556
Provision (benefit) for income taxes	25,952	288	20,149	(2,085)
Defense Electronics | Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenue	50,795	62,574	161,061	190,492
Cost of goods and services	39,059	52,780	125,208	166,292
Gross profit	11,736	9,794	35,853	24,200
Selling, general and administrative expenses	6,114	7,875	26,423	27,102
Income from discontinued operations	5,622	1,919	9,430	(2,902)
Interest income, net	0	0	2	1
Gain on sale of business	108,949	0	108,949	5,291
Other, net	(1,114)	261	(604)	1,166
Total other income (expense)	107,835	261	108,347	6,458
Income from discontinued operations before taxes	113,457	2,180	117,777	3,556
Provision (benefit) for income taxes	25,952	288	20,149	(2,085)
Income from discontinued operations	$ 87,505	$ 1,892	$ 97,628	$ 5,641