Goodwill and Intangible Assets - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Sep. 30, 2020
Goodwill and Intangible Assets [Line Items]
Goodwill	$ 37,323		$ 35,669
Amortization of intangible assets	$ 1,693	$ 1,608
Minimum
Goodwill and Intangible Assets [Line Items]
Estimated useful lives of intangible assets (in years)	2 years
Maximum
Goodwill and Intangible Assets [Line Items]
Estimated useful lives of intangible assets (in years)	7 years