Share-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	6 Months Ended	12 Months Ended
Dec. 31, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for issuance	798,586	798,586
Number of Shares, Granted	526	652	683
Number of shares withheld		21,832	14,020	10,319
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount	$ 4.7	$ 4.7
SICP Awards to Non-employee directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to the awards to Non employee directors	0.3	$ 0.3
Weighted average grant-date fair value of awards granted		$ 130.36	$ 117.11
SICP Awards to Key Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value		$ 90.60	$ 76.31
Number of Shares, Granted		69,620	69,903
Weighted average grant-date fair value of awards granted		$ 117.61	$ 100.76
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Nonvested	$ 24.0	$ 24.0	$ 28.8	$ 20.2
Stock and Incentive Compensation Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for issuance	322,509	322,509

Aggregate number of common shares reserved for future issuance.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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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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Intrinsic value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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Number of shares used to settle grantee's tax withholding obligation for award under share-based payment arrangement.

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