Summary of Activity Under Stock Plans (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-Based Payment Arrangement [Abstract]
Intrinsic value of options exercised	$ 41.2	$ 17.8	$ 25.4
Cash received from stock option exercises	51.7	35.8	38.4
Tax benefit related to stock award exercises	5.4	2.6	4.9
Stock-based compensation	21.2	17.1	14.7
Tax benefit related to stock-based compensation	$ 1.7	$ 1.7	$ 1.6

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
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-Publisher FASB
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Amount of tax benefit for recognition of expense of award under share-based payment arrangement.

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Amount of tax benefit from exercise of option under share-based payment arrangement.

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Amount of cash inflow from exercise of option under share-based payment arrangement.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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