SCHEDULE II VALUATION AND QUALIFYING ACCOUNTS - Schedule of valuation and qualifying accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Allowance for Doubtful Accounts
Segment Reporting Information [Line Items]
Balance at Beginning of  Year	$ 8,178	$ 7,588	$ 6,115
Additions	795	5,175	6,253
Reductions	(393)	(4,584)	(4,799)
Other	207	(1)	19
Balance at End of Year	8,787	8,178	7,588
Inventory valuation
Segment Reporting Information [Line Items]
Balance at Beginning of  Year	18,903	15,218	15,940
Additions	24,400	6,771	1,947
Reductions	(12,099)	(3,412)	(2,614)
Other	401	326	(55)
Balance at End of Year	31,605	18,903	15,218
Deferred tax valuation allowance
Segment Reporting Information [Line Items]
Balance at Beginning of  Year	9,824	10,823	8,520
Additions	601	0	2,303
Reductions	0	(999)	0
Other	0	0	0
Balance at End of Year	$ 10,425	$ 9,824	$ 10,823