Stock-based Compensation (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	12 Months Ended
Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Dec. 31, 2022
Restricted Stock Units (RSUs)
Share-based Payment activity [Roll Forward]
Unvested at beginning of period (in shares)	990,100	841,300	841,300
Granted (in shares)	0	0
Vested (in shares)	(191,500)	(145,600)
Forfeited (in shares)	(22,600)	(7,300)
Unvested at end of period (in shares)	776,000.0	688,400	990,100	841,300
Performance Shares [Member]
Share-based Payment activity [Roll Forward]
Unvested at beginning of period (in shares)	458,100	567,000.0	567,000.0
Granted (in shares)	900	31,000.0
Vested (in shares)	(109,000.0)	(257,200)
Forfeited (in shares)	(6,500)	(24,400)
Unvested at end of period (in shares)	343,500	316,400	458,100	567,000.0
Share-based Payment Arrangement [Member]
Share-based Payment activity [Roll Forward]
Unvested at beginning of period (in shares)	1,448,200	1,408,300	1,408,300
Granted (in shares)	900	31,000.0
Vested (in shares)	(300,500)	(402,800)
Forfeited (in shares)	(29,100)	(31,700)
Unvested at end of period (in shares)	1,119,500	1,004,800	1,448,200	1,408,300
Share-based Payment activity, additional disclosures [Abstract]
Weighted average grant date fair value, beginning of period (in dollars per share)	$ 175.07	$ 170.78	$ 170.78
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	187.26	111.33
Weighted average grant date fair value, vested (in dollars per share)	182.60	115.92
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	172.26	125.84
Weighted average grant date fair value, end of period (in dollars per share)	$ 172.40	$ 192.36	$ 175.07	$ 170.78
Weighted average remaining contractual life, unvested shares outstanding	1 year 3 months 18 days	1 year 7 months 28 days	1 year 7 months 28 days	1 year 9 months 14 days
Unamortized deferred compensation cost	$ 61.0

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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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).

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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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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
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-Section 50
-Paragraph 2
-Subparagraph (c)(2)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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Weighted average remaining contractual term for equity-based awards excluding options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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