Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Valuation allowance - deferred tax assets
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period	$ 2,186	$ 4,372	$ 3,810
Charged to costs and expenses	790	(2,186)	670
Charged to Other Accounts	0	0	0
Deductions	0	0	108
Balance at end of period	2,976	2,186	4,372
Reserve for future credit returns and pricing adjustments
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period	930	1,476	2,677
Charged to costs and expenses	17,087	15,477	17,816
Charged to Other Accounts	0	0	0
Deductions	16,886	16,023	19,017
Balance at end of period	$ 1,131	$ 930	$ 1,476