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Fair Value Measurements - Narrative (Details) € in Millions, $ in Millions |  | 2 Months Ended | 3 Months Ended | 9 Months Ended | 12 Months Ended |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Jan. 05, 2024 USD ($) | Jan. 05, 2024 USD ($) | Sep. 29, 2024 USD ($) | Mar. 31, 2024 USD ($) | Oct. 01, 2023 USD ($) | Apr. 02, 2023 USD ($) | Sep. 29, 2024 USD ($) | Oct. 01, 2023 USD ($) | Dec. 31, 2023 USD ($) | Jul. 17, 2024 USD ($) derivative | May 31, 2024 USD ($) | Feb. 08, 2024 EUR (€) | Nov. 02, 2023 EUR (€) | Feb. 14, 2022 country | Jan. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Unrealized gain (loss) on derivatives |  |  |  |  |  |  |  |  | $ (3.6) |  |  |  |  |  |
Payments for derivative instrument, investing activities |  |  |  |  |  |  | $ 2.4 | $ 0.0 |  |  |  |  |  |  |
Gain on forward contract |  |  | $ 0.0 |  | $ 0.0 |  | 1.2 | 0.0 |  |  |  |  |  |  |
Payment for contingent consideration liability, financing activities |  |  |  |  |  |  | 0.0 | 2.5 |  |  |  |  |  |  |
Measured on Recurring Basis |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Money market funds |  |  | 6.9 |  |  |  | 6.9 |  | 42.5 |  |  |  |  |  |
Foreign Exchange Forward |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Derivative, notional amount | € |  |  |  |  |  |  |  |  |  |  |  | € 17.0 | € 90.0 |  |
Unrealized gain (loss) on derivatives |  |  |  |  |  |  | (0.6) |  | (3.6) |  |  |  |  |  |
Foreign currency forward contract, liability, net |  |  | 0.6 |  |  |  | 0.6 |  | 3.6 |  |  |  |  |  |
Payments for derivative instrument, investing activities | $ 2.4 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Gain on forward contract |  |  |  | $ 1.2 |  |  |  |  |  |  |  |  |  |  |
Derivative instruments not designated as hedging instruments, loss |  | $ 2.4 |  |  |  |  |  |  |  |  |  |  |  |  |
Foreign Exchange Forward | Measured on Recurring Basis |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Foreign currency forward contract, liability, net |  |  | 0.6 |  |  |  | 0.6 |  | 3.6 |  |  |  |  |  |
Interest Rate Swap |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Derivative, notional amount |  |  |  |  |  |  |  |  |  | $ 50.0 |  |  |  |  |
Foreign currency forward contract, liability, net |  |  | 0.8 |  |  |  | 0.8 |  |  |  |  |  |  |  |
Derivative instruments not designated as hedging instruments, loss |  |  | 0.8 |  |  |  |  |  |  |  |  |  |  |  |
Number of interest rate swaps | derivative |  |  |  |  |  |  |  |  |  | 2 |  |  |  |  |
Derivative liability, current |  |  | 0.6 |  |  |  | 0.6 |  |  |  |  |  |  |  |
Derivative liability, noncurrent |  |  | 0.2 |  |  |  | 0.2 |  |  |  |  |  |  |  |
Derivative instruments not designated as hedging instruments, gain (loss), net |  |  | (0.7) |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from Derivative Instrument, Financing Activities |  |  | 0.1 |  |  |  |  |  |  |  |  |  |  |  |
Interest Rate Swap | Measured on Recurring Basis |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Foreign currency forward contract, liability, net |  |  | 0.8 |  |  |  | 0.8 |  |  |  |  |  |  |  |
Brazil |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Indemnification liabilities, expense (income) |  |  |  |  |  |  |  | 0.1 |  |  |  |  |  |  |
Brazil | Measured on Recurring Basis |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Indemnification |  |  | (2.7) |  |  |  | (2.7) |  | (3.0) |  |  |  |  |  |
Brazil | Maximum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Indemnification liability |  |  | 8.8 |  |  |  | 8.8 |  |  |  |  |  |  |  |
EMEA | Measured on Recurring Basis |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Indemnification |  |  | $ (2.1) |  |  |  | $ (2.1) |  |  |  |  |  |  |  |
Greenwood/Asher |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Payment for contingent consideration liability, financing activities |  |  |  |  |  |  |  | $ 1.4 |  |  |  |  |  |  |
Motion Recruitment Partners, LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Contingent consideration, maximum |  |  |  |  |  |  |  |  |  |  | $ 60.0 |  |  |  |
PersolKelly Pte. Ltd. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Equity method investment, ownership percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 49.00%
Number of geographies in which entity operates | country |  |  |  |  |  |  |  |  |  |  |  |  |  | 10 |
Equity ownership, excluding consolidated entity and equity method investee, percentage |  |  | 2.50% |  |  |  | 2.50% |  |  |  |  |  |  |  |
Equity securities without readily determinable fair value, with changes in fair value in net income |  |  | $ 6.4 |  |  |  | $ 6.4 |  |  |  |  |  |  |  |
Other Assets |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Money market funds |  |  | 6.9 |  |  |  | 6.9 |  | 8.0 |  |  |  |  |  |
Level 3 | Measured on Recurring Basis |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Money market funds |  |  | 0.0 |  |  |  | 0.0 |  | 0.0 |  |  |  |  |  |
Level 3 | Foreign Exchange Forward | Measured on Recurring Basis |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Foreign currency forward contract, liability, net |  |  | 0.0 |  |  |  | 0.0 |  | 0.0 |  |  |  |  |  |
Level 3 | Interest Rate Swap | Measured on Recurring Basis |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Foreign currency forward contract, liability, net |  |  | 0.0 |  |  |  | 0.0 |  |  |  |  |  |  |  |
Level 3 | Brazil |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Indemnification liability |  |  |  |  |  |  |  |  | 3.0 |  |  |  |  |  |
Level 3 | Brazil | Measured on Recurring Basis |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Indemnification |  |  | (2.7) |  |  |  | (2.7) |  | (3.0) |  |  |  |  |  |
Level 3 | EMEA |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disposition, increase (decrease) in indemnification liabilities |  |  | 0.1 |  |  |  |  |  |  |  |  |  |  |  |
Level 3 | EMEA | Measured on Recurring Basis |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Indemnification |  |  | (2.1) |  |  |  | (2.1) |  |  |  |  |  |  |  |
Level 3 | Greenwood/Asher |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Payment for contingent consideration liability |  |  |  |  |  | $ 3.3 |  |  |  |  |  |  |  |  |
Level 3 | Motion Recruitment Partners, LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Business combination, contingent consideration, liability |  |  | 3.4 |  |  |  | 3.4 |  |  |  |  |  |  |  |
Contingent consideration, maximum |  |  | 60.0 |  |  |  | 60.0 |  |  |  |  |  |  |  |
Level 3 | Accounts Payable and Accrued Liabilities | Brazil |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Indemnification liability |  |  | 0.1 |  |  |  | 0.1 |  | 0.1 |  |  |  |  |  |
Level 3 | Other Long Term Liabilities | Brazil |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Indemnification liability |  |  | $ 2.6 |  |  |  | $ 2.6 |  | $ 2.9 |  |  |  |  |  |

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- Definition Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. 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