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Commitments, Contingencies and Off-Balance Sheet Arrangements - Additional Information (Detail) | 12 Months Ended
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Dec. 31, 2021 USD ($) ft² Employee LetterOfCredit | Dec. 31, 2020 USD ($) | Dec. 31, 2019 USD ($)
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |  |  |
Number of square feet | ft² | 360,000 |  |
Number of employees will accommodate at new facility | Employee | 2,000 |  |
Total rent expense | $ 153,400,000 | $ 154,000,000.0 | $ 148,100,000
Aggregate amount of maximum earnout obligations related to acquisitions | 1,873,900,000 | 1,128,100,000 |
Aggregate amount of maximum earnout obligations related to acquisitions, recorded in consolidated balance sheet | 988,500,000 | 592,200,000 |
Aggregate amount of earnout obligation expected settlement in cash or stock at option | 670,300,000 | 493,700,000 |
Aggregate amount of earnout obligation expected settlement in cash | $ 318,200,000 | $ 98,500,000 |
Ownership interest | 50.00% |  |
Debt | $ 22,600,000 |  |
Liabilities recorded on self-insurance | 18,300,000 |  |
Income tax credits and adjustments | $ 108,000,000.0 |  |
Security Deposit [Member] |  |  |
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |  |  |
Number of letters of credit issued | LetterOfCredit | 2 |  |
Collateral [Member] |  |  |
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |  |  |
Number of letters of credit issued | LetterOfCredit | 1 |  |
Self-Insurance Deductibles [Member] |  |  |
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |  |  |
Number of letters of credit issued | LetterOfCredit | 2 |  |
Rent-A-Captive Facility [Member] |  |  |
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |  |  |
Number of letters of credit issued | LetterOfCredit | 8 |  |
Errors And Omissions [Member] | Up to $4.5 Million [Member] |  |  |
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |  |  |
Insurance claims, amount retained | $ 2,000,000.0 |  |
Errors And Omissions [Member] | Up to $10 Million [Member] |  |  |
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |  |  |
Insurance claims, amount retained | 15,000,000.0 |  |
Insurance claim arise during ordinary course of business | 15,000,000.0 |  |
Errors And Omissions [Member] | Up to $20.0 Million [Member] |  |  |
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |  |  |
Insurance claims, amount retained | 20,000,000.0 |  |
Errors And Omissions [Member] | Up to $27.0 Million [Member] |  |  |
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |  |  |
Insurance claims, amount retained | 10,000,000.0 |  |
Letter of Credit [Member] | Security Deposit [Member] |  |  |
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |  |  |
Debt | 600,000 |  |
Letter of Credit [Member] | Collateral [Member] |  |  |
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |  |  |
Debt | 900,000 |  |
Letter of Credit [Member] | Self-Insurance Deductibles [Member] |  |  |
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |  |  |
Debt | 9,400,000 |  |
Liabilities recorded on self-insurance | 18,300,000 |  |
Letter of Credit [Member] | Rent-A-Captive Facility [Member] |  |  |
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |  |  |
Debt | 6,100,000 |  |
Minimum [Member] | Errors And Omissions [Member] |  |  |
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |  |  |
Actuarial range value | 3,700,000 |  |
Minimum [Member] | Errors And Omissions [Member] | Up to $4.5 Million [Member] |  |  |
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |  |  |
Insurance claim arise during ordinary course of business | 15,000,000.0 |  |
Minimum [Member] | Errors And Omissions [Member] | Up to $20.0 Million [Member] |  |  |
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |  |  |
Insurance claim arise during ordinary course of business | 100,000,000.0 |  |
Minimum [Member] | Errors And Omissions [Member] | Up to $27.0 Million [Member] |  |  |
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |  |  |
Insurance claim arise during ordinary course of business | $ 225,000,000.0 |  |
Minimum [Member] | Unconsolidated Investments in Enterprises [Member] |  |  |
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |  |  |
Ownership interest | 1.00% |  |
Maximum [Member] |  |  |
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |  |  |
Ownership interest | 50.00% |  |
Maximum [Member] | Errors And Omissions [Member] |  |  |
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |  |  |
Actuarial range value | $ 5,800,000 |  |
Maximum [Member] | Errors And Omissions [Member] | Up to $4.5 Million [Member] |  |  |
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |  |  |
Insurance claim arise during ordinary course of business | 100,000,000.0 |  |
Maximum [Member] | Errors And Omissions [Member] | Up to $20.0 Million [Member] |  |  |
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |  |  |
Insurance claim arise during ordinary course of business | 225,000,000.0 |  |
Maximum [Member] | Errors And Omissions [Member] | Up to $27.0 Million [Member] |  |  |
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |  |  |
Insurance claim arise during ordinary course of business | $ 365,000,000.0 |  |
Maximum [Member] | Unconsolidated Investments in Enterprises [Member] |  |  |
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |  |  |
Ownership interest | 50.00% |  |
Tax Increment Financing [Member] |  |  |
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |  |  |
Property tax credits receivable period | 15 years |  |
Economic development for growing economy tax credit | $ 32,600,000 |  |
Tax Increment Financing [Member] | Minimum [Member] |  |  |
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |  |  |
Property tax credit expect to receive | 60,000,000.0 |  |
Tax Increment Financing [Member] | Maximum [Member] |  |  |
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |  |  |
Property tax credit expect to receive | $ 90,000,000.0 |  |

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