Summary of Significant Accounting Policies - Revenue Recognition (Details)	12 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Revenue From Products And Services Transferred Over Time Risk \| Revenue Benchmark \| Transferred over time
Disaggregation of Revenue [Line Items]
Concentration risk percentage	1.00%	5.00%	4.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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