Intangible Assets, Goodwill and Acquisitions - Additional Information (Details) $ in Millions	3 Months Ended	6 Months Ended
Mar. 31, 2022 USD ($) Company	Mar. 31, 2021 USD ($) Company	Mar. 31, 2022 USD ($) Company	Mar. 31, 2021 USD ($) Company
Finite Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 12.0	$ 12.5	$ 25.5	$ 26.4
Number of unrelated maintenance services companies acquired \| Company	6	4	6	4
Consideration paid, net of cash acquired			$ 84.4	$ 75.7
Number of unrelated companies allocated between maintenance services and development services \| Company	1	2	1	2
Unrelated Maintenance Services Companies
Finite Lived Intangible Assets [Line Items]
Acquisition of operations, Percentage	100.00%	100.00%	100.00%	100.00%
Consideration paid, net of cash acquired			$ 84.4	$ 75.7
Customer Relationships
Finite Lived Intangible Assets [Line Items]
Identifiable assets acquired related to intangible assets	$ 16.8	$ 18.0	$ 16.8	$ 18.0

Number of unrelated companies allocated between maintenance services and development services.

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Number of unrelated maintenance services companies acquired.

+ References

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The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Percentage of voting equity interests acquired at the acquisition date in the business combination.

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The amount of identifiable intangible assets recognized as of the acquisition date.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The cash outflow associated with the acquisition of a business, net of the cash acquired from the purchase.

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