Segments - Summary of Residential and Commercial Segment Reporting Information (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Business Transformation Costs [Line Items]
Business acquisition acquisition costs completed acquisitions	$ 1.4	$ 3.9	$ 3.9	$ 4.4
Inventory step up adjustments relating to business acquisitions		1.2		1.2
Costs Of Reduction In Workforce	0.2		0.2
Legal expenses		0.1	0.2	0.4
Other costs, other	$ 0.2	$ 0.1	$ 0.7	0.2
IPO [Member]
Business Transformation Costs [Line Items]
Costs related to an incentive plan				$ 0.1

Business transformation costs.

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- Definition

Costs of reduction in workforce.

+ References

No definition available.

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- Definition

Costs related to an incentive plan.

+ References

No definition available.

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- Definition

Other miscellaneous expenses.

+ References

No definition available.

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- Definition

This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 23
-URI https://asc.fasb.org/extlink&oid=123586518&loc=d3e1043-128460

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- Definition

This element represents the amount of any measurement period adjustment (as defined) realized during the reporting period to inventory acquired in connection with a business combination for which the initial accounting was incomplete.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 4A
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=128092470&loc=SL65897772-128472

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- Definition

The amount of expense provided in the period for legal costs incurred on or before the balance sheet date pertaining to resolved, pending or threatened litigation, including arbitration and mediation proceedings.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.3)
-URI https://asc.fasb.org/extlink&oid=126953954&loc=SL114868664-224227

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