Revenue - Narrative (Details) - USD ($)	12 Months Ended
Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Impairment loss on contract assets	$ 0	$ 0
Remaining performance obligations	$ 91,135,000	$ 117,600,000
Transferred over Time \| Revenue from Contract with Customer Benchmark
Disaggregation of Revenue [Line Items]
Percentage of concentration risk	59.00%	56.00%

Amount of impairment loss for asset recognized from cost incurred to obtain or fulfill contract with customer.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 340
-SubTopic 40
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=68051541&loc=SL49131252-203054

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
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No definition available.

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Amount of transaction price allocated to performance obligation that has not been recognized as revenue.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
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