Divestitures, Discontinued Operations and Assets and Liabilities Held for Sale - Summary of Discontinued Operations (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Discontinued Operations and Disposal Groups [Abstract]
Total revenues	$ 34.5	$ 111.7	$ 0.0	$ 206.4
Pretax (loss) earnings from operations	(1.4)	20.5	(18.5)	16.4
Pretax gain (loss) on divestiture and sales of assets	2.3	(1.0)	2.3	(1.0)
Pretax (loss) earnings	0.9	19.5	(16.2)	15.4
Income tax expense (benefit)	0.2	6.2	(0.0)	5.2
Earnings (loss) from discontinued operations, net of income tax expense (benefit)	$ 0.7	$ 13.3	$ (12.2)	$ 10.2

Amount before tax of income (loss) from a discontinued operation. Includes, but is not limited to, the income (loss) from operations during the phase-out period, gain (loss) on disposal, gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and adjustments to a prior period gain (loss) on disposal.

Amount of tax expense (benefit) related to a discontinued operation. Includes, but is not limited to, tax expense (benefit) related to income (loss) from operations during the phase-out period, tax expense (benefit) related to gain (loss) on disposal, tax expense (benefit) related to gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and tax expense (benefit) related to adjustments of a prior period gain (loss) on disposal.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-10

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482659/740-20-45-2

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Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
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-URI https://asc.fasb.org//1943274/2147483499/205-20-50-5B

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Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 205
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-Topic 205
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Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 205
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483499/205-20-50-1

+ Details

- Definition

Amount after tax of income (loss) from a discontinued operation attributable to the parent. Includes, but is not limited to, the income (loss) from operations during the phase-out period, gain (loss) on disposal, gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and adjustments to a prior period gain (loss) on disposal.

+ References + Details