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Accounting Policies 401k(Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Worksite Employee Plan [Member] |  |  |
Defined Contribution Plan [Abstract] |  |  |
Defined Contribution Plan, Employer Discretionary Contribution Amount | $ 374.5 | $ 328.5 | $ 244.1
Worksite Employee Plan [Member] | Minimum [Member] |  |  |
Defined Contribution Plan [Abstract] |  |  |
Defined Contribution Plan, Employer Matching Contribution, Percent of Match | 0.00% |  |
Worksite Employee Plan [Member] | Maximum [Member] |  |  |
Defined Contribution Plan [Abstract] |  |  |
Defined Contribution Plan, Employer Matching Contribution, Percent of Match | 6.00% |  |
CorporatePlan [Domain] |  |  |
Defined Contribution Plan [Abstract] |  |  |
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent | 6.00% | 6.00% | 6.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Match | 100.00% |  |
Defined Contribution Plan, Employer Discretionary Contribution Amount | $ 16.9 | $ 14.4 | $ 8.2

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- Definition 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. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 70 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480794/715-70-50-1 + Details
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- Definition Amount of discretionary contributions made by an employer to a defined contribution plan. + References No definition available. + Details
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- Definition Percentage employer matches of the employee's percentage contribution matched. + References No definition available. + Details
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- Definition Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan. + References No definition available. + Details
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- Details
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