Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Allowance For Credit Losses
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance At Beginning of Year	$ 583	$ 2,377	$ 1,900
Amount of Charge (Benefit) To Expenses	76	(1,122)	432
Deductions and Adjustments	(132)	(672)	45
Balance At End of Year	527	583	2,377
Valuation Allowance
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance At Beginning of Year	2,948	2,565	133
Amount of Charge (Benefit) To Expenses	472	658	2,432
Deductions and Adjustments	(540)	(275)	0
Balance At End of Year	$ 2,880	$ 2,948	$ 2,565