Segment Data and Related Information (Narrative) (Details)	3 Months Ended		6 Months Ended
	Mar. 31, 2020 customer	Mar. 31, 2019 customer	Mar. 31, 2020 segment	Mar. 31, 2019	Dec. 31, 2019	Sep. 30, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of reporting segments | segment			2
Concentration risk, customers	3
Concentration risk percentage	100.00%	100.00%
Percentage of long-lived assets located in the United States					96.00%	85.00%
Customer Concentration Risk
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Concentration risk, customers		4
Customer Concentration Risk | Sales Revenue, Segment
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Concentration risk percentage	56.00%	67.00%	53.00%	71.00%