Fair Value Measurements - Schedule of Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Oct. 03, 2021	Jan. 03, 2021
Assets, Fair Value Disclosure [Abstract]
Investment in Persol Holdings	$ 222.6	$ 164.2
Measured on Recurring Basis
Assets, Fair Value Disclosure [Abstract]
Money market funds	6.5	120.3
Investment in Persol Holdings	222.6	164.2
Total assets at fair value	229.1	284.5
Liabilities, Fair Value Disclosure [Abstract]
Brazil indemnification	(2.5)	(2.6)
Total liabilities at fair value	(6.6)	(6.4)
Measured on Recurring Basis \| Greenwood/Asher
Liabilities, Fair Value Disclosure [Abstract]
Earnout, fair value	(4.1)	(2.1)
Measured on Recurring Basis \| Insight
Liabilities, Fair Value Disclosure [Abstract]
Earnout, fair value	0.0	(1.7)
Measured on Recurring Basis \| Level 1
Assets, Fair Value Disclosure [Abstract]
Money market funds	6.5	120.3
Investment in Persol Holdings	222.6	164.2
Total assets at fair value	229.1	284.5
Liabilities, Fair Value Disclosure [Abstract]
Brazil indemnification	0.0	0.0
Total liabilities at fair value	0.0	0.0
Measured on Recurring Basis \| Level 1 \| Greenwood/Asher
Liabilities, Fair Value Disclosure [Abstract]
Earnout, fair value	0.0	0.0
Measured on Recurring Basis \| Level 1 \| Insight
Liabilities, Fair Value Disclosure [Abstract]
Earnout, fair value	0.0	0.0
Measured on Recurring Basis \| Level 2
Assets, Fair Value Disclosure [Abstract]
Money market funds	0.0	0.0
Investment in Persol Holdings	0.0	0.0
Total assets at fair value	0.0	0.0
Liabilities, Fair Value Disclosure [Abstract]
Brazil indemnification	0.0	0.0
Total liabilities at fair value	0.0	0.0
Measured on Recurring Basis \| Level 2 \| Greenwood/Asher
Liabilities, Fair Value Disclosure [Abstract]
Earnout, fair value	0.0	0.0
Measured on Recurring Basis \| Level 2 \| Insight
Liabilities, Fair Value Disclosure [Abstract]
Earnout, fair value	0.0	0.0
Measured on Recurring Basis \| Level 3
Assets, Fair Value Disclosure [Abstract]
Money market funds	0.0	0.0
Investment in Persol Holdings	0.0	0.0
Total assets at fair value	0.0	0.0
Liabilities, Fair Value Disclosure [Abstract]
Brazil indemnification	(2.5)	(2.6)
Total liabilities at fair value	(6.6)	(6.4)
Measured on Recurring Basis \| Level 3 \| Greenwood/Asher
Liabilities, Fair Value Disclosure [Abstract]
Earnout, fair value	(4.1)	(2.1)
Measured on Recurring Basis \| Level 3 \| Insight
Liabilities, Fair Value Disclosure [Abstract]
Earnout, fair value	$ 0.0	$ (1.7)

Earnout, Fair Value Disclosure

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- Definition

Indemnification, Fair Value Disclosure

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- Definition

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

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Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI), classified as current.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=123594786&loc=SL75136599-209740

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Fair value of financial and nonfinancial obligations.

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Investment in short-term money-market instruments (such as commercial paper, banker's acceptances, repurchase agreements, government securities, certificates of deposit, and so forth) which are highly liquid (that is, readily convertible to known amounts of cash) and so near their maturity that they present an insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify as cash equivalents by definition. Original maturity means an original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

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