Segment Data and Related Information - Narrative (Details)	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020 customer	Mar. 31, 2021 segment customer	Mar. 31, 2020	Sep. 30, 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of reporting segments | segment			2
Percentage of long-lived assets located in the United States	98.00%		98.00%		97.00%
Customer Concentration Risk
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Concentration risk, customers | customer		3	3
Sales Revenue, Segment | Customer Concentration Risk
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
% of Revenue	68.00%	56.00%	69.00%	53.00%