Fair Value Measurements - Narrative (Details) - USD ($) $ in Millions	3 Months Ended				12 Months Ended
	Oct. 03, 2021	Jul. 04, 2021	Apr. 04, 2021	Mar. 29, 2020	Jan. 02, 2022	Jan. 03, 2021	Dec. 29, 2019	Mar. 08, 2021	Nov. 18, 2020	Aug. 18, 2020	Jan. 14, 2020	Dec. 31, 2006
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Proceeds from (investment in) equity securities					$ 5.0
Goodwill impairment charge				$ 147.7	0.0	$ 147.7	$ 0.0
Brazil
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Indemnification liability										$ 2.5
Business Combination, Indemnification Liabilities, Expense					(0.2)	2.6
Greenwood/Asher
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration, liability									$ 2.1
Expense related to earnout liability					2.5
Insight
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration, liability											$ 1.6
Expense related to earnout liability		$ 0.1			0.1	0.1
Payment for contingent consideration liability	$ 1.8
Persol Holdings Investment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cost of equity securities					18.0	20.1						$ 33.9
Business Talent Group, LLC
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Proceeds from (investment in) equity securities		$ 5.0
Kenzie Academy Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, FV-NI and without readily determinable fair value						1.4		$ 1.4
Debt and equity securities, realized gain (loss)			$ (1.4)
Other Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds					6.5	5.1
Level 3 | Brazil
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Indemnification liability					2.4	2.6
Level 3 | Greenwood/Asher
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration, liability					4.6	2.1
Level 3 | Insight
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration, liability						$ 1.7
Level 3 | Other Long Term Liabilities | Greenwood/Asher
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration, liability					2.3
Level 3 | Accounts Payable and Accrued Liabilities | Greenwood/Asher
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration, liability					$ 2.3