Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Valuation allowance - deferred tax assets
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period	$ 2,976	$ 2,186	$ 4,372
Charged to costs and expenses	278	790	(2,186)
Charged to Other Accounts	0	0	0
Deductions	0	0	0
Balance at end of period	3,254	2,976	2,186
Reserve for future credit returns and pricing adjustments
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period	1,131	930	1,476
Charged to costs and expenses	20,205	17,087	15,477
Charged to Other Accounts	0	0	0
Deductions	(20,025)	(16,886)	(16,023)
Balance at end of period	$ 1,311	$ 1,131	$ 930