Intangible Assets, Goodwill and Acquisitions - Additional Information (Details) $ in Millions	9 Months Ended	12 Months Ended
Sep. 30, 2017 USD ($)	Sep. 30, 2019 USD ($) Company	Sep. 30, 2018 USD ($) Company
Finite Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 92.9	$ 56.3	$ 104.9
Weighted average amortization period for intangible assets		17 years 10 months 24 days
Acquisition of operations, Percentage		100.00%	100.00%
Number of unrelated maintenance services companies acquired \| Company		6	5
Consideration paid, net of cash acquired	$ 53.8	$ 64.0	$ 104.4
Customer Relationships and Non-compete Agreements
Finite Lived Intangible Assets [Line Items]
Identifiable assets acquired related to intangible assets		$ 17.2	$ 24.5

Number of unrelated maintenance services companies acquired.

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- Definition

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

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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- Definition

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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