Goodwill - Changes in the Net Carrying Amount of Goodwill (Details) - USD ($) $ in Millions	9 Months Ended
Oct. 01, 2017	Jan. 01, 2017
Goodwill [Roll Forward]
Goodwill, Gross		$ 189.3
Accumulated Impairment Losses		(100.9)
Allocation of Goodwill	$ 0.0
Additions to Goodwill	18.7
Goodwill	107.1	88.4
Americas Commercial
Goodwill [Roll Forward]
Goodwill, Gross		40.0
Accumulated Impairment Losses		(16.4)
Allocation of Goodwill	(23.6)
Goodwill	0.0	23.6
Americas PT
Goodwill [Roll Forward]
Goodwill, Gross		37.9
Accumulated Impairment Losses		0.0
Allocation of Goodwill	(37.9)
Goodwill	0.0	37.9
EMEA Commercial
Goodwill [Roll Forward]
Goodwill, Gross		50.4
Accumulated Impairment Losses		(50.4)
Allocation of Goodwill	0.0
Goodwill	0.0	0.0
EMEA PT
Goodwill [Roll Forward]
Goodwill, Gross		22.0
Accumulated Impairment Losses		(22.0)
Allocation of Goodwill	0.0
Goodwill	0.0	0.0
APAC Commercial
Goodwill [Roll Forward]
Goodwill, Gross		12.1
Accumulated Impairment Losses		(12.1)
Allocation of Goodwill	0.0
Goodwill	0.0	0.0
APAC PT
Goodwill [Roll Forward]
Goodwill, Gross		0.0
Accumulated Impairment Losses		0.0
Allocation of Goodwill	0.0
Goodwill	0.0	0.0
OCG
Goodwill [Roll Forward]
Goodwill, Gross		26.9
Accumulated Impairment Losses		0.0
Allocation of Goodwill	(26.9)
Goodwill	0.0	26.9
Americas Staffing
Goodwill [Roll Forward]
Goodwill, Gross		0.0
Accumulated Impairment Losses		0.0
Allocation of Goodwill	25.9
Additions to Goodwill	18.7
Goodwill	44.6	0.0
Global Talent Solutions
Goodwill [Roll Forward]
Goodwill, Gross		0.0
Accumulated Impairment Losses		0.0
Allocation of Goodwill	62.5
Goodwill	62.5	0.0
International Staffing
Goodwill [Roll Forward]
Goodwill, Gross		0.0
Accumulated Impairment Losses		0.0
Allocation of Goodwill	0.0
Goodwill	$ 0.0	$ 0.0

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975

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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

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Amount before accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of accumulated impairment loss for an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of transfers into (out of) an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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