INCOME TAXES - Components of Income before taxes and discontinued operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Domestic	$ 57,059	$ 28,530	$ 23,437
Non-U.S.	54,120	40,175	22,786
Income (loss) before taxes from continuing operations	$ 111,179	$ 68,705	$ 46,223