Description of risks that arise due to the volume of business transacted with a particular customer. At a minimum, the description informs financial statement users of the general nature of the risk, but excludes "Information about Major Customers" that may be disclosed elsewhere (for instance, segment disclosures).

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Description of risks that arise due to concentrations of operating facilities, revenues, assets, customers, vendors or the like in a certain geographic area, either domestic or foreign. The description may address risks inherent in the geographic area, and, at a minimum, informs users of the general nature of the risk, but excludes "Information about Geographic Areas" that may be disclosed elsewhere (for instance, segment disclosures)..

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Number of Countries, Outside the United States, that Exceeded 10%

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Enterprise-wide Disclosures and Concentration of Business - Additional Information (Detail)	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017 country customer	Sep. 30, 2016 country customer
Concentration Risk [Line Items]
Concentration Risk, Geographic	No individual country, other than the United States, generated more than 10% of net operating revenues in these years.
Concentration Risk, Customer	The Company did not have any customer that generated greater than 10% of its net operating revenues in fiscal 2018, 2017 and 2016.
Geographic Concentration Risk \| Net Operating Revenue
Concentration Risk [Line Items]
Number of Countries, Outside the United States, that Exceeded 10% \| country		0	0
Customer Concentration Risk \| Net Operating Revenue
Concentration Risk [Line Items]
Number of Customers that Exceeded 10% \| customer		0	0
United States \| Geographic Concentration Risk \| Net Operating Revenue
Concentration Risk [Line Items]
Concentration Risk, Percentage	45.00%	47.00%	52.00%