Revenue - Unearned Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Unearned Revenue [Roll Forward]
Unearned revenue, beginning of period	$ 15,500	$ 9,300
Revenue recognized	13,200	7,500
Unearned revenue, end of period	$ 21,600	$ 15,500