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v3.20.4

Business Segments Disaggregated Revenue (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Revenue from External Customer [Line Items] |  |  |
Revenues | $ 3,950.6 | $ 3,923.9 | $ 3,399.8
Apex |  |  |
Revenue from External Customer [Line Items] |  |  |
Revenues | 2,421.2 | 2,520.0 | 2,300.3
Apex | Assignment |  |  |
Revenue from External Customer [Line Items] |  |  |
Revenues | 2,040.3 | 2,190.9 | 2,050.1
Apex | Consulting |  |  |
Revenue from External Customer [Line Items] |  |  |
Revenues | 380.9 | 329.1 | 250.2
Oxford |  |  |
Revenue from External Customer [Line Items] |  |  |
Revenues | 525.2 | 605.7 | 606.5
Oxford | Assignment |  |  |
Revenue from External Customer [Line Items] |  |  |
Revenues | 468.6 | 549.4 | 558.1
Oxford | Consulting |  |  |
Revenue from External Customer [Line Items] |  |  |
Revenues | 56.6 | 56.3 | 48.4
ECS |  |  |
Revenue from External Customer [Line Items] |  |  |
Revenues | 1,004.2 | 798.2 | 493.0
ECS | Firm-fixed-price |  |  |
Revenue from External Customer [Line Items] |  |  |
Revenues | 272.0 | 214.0 | 133.1
ECS | Time and materials |  |  |
Revenue from External Customer [Line Items] |  |  |
Revenues | 322.6 | 267.8 | 143.4
ECS | Cost reimbursable |  |  |
Revenue from External Customer [Line Items] |  |  |
Revenues | $ 409.6 | $ 316.4 | $ 216.5

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- Definition Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 22 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=115929826&loc=d3e8736-108599 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 32 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=115929826&loc=d3e8933-108599 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 22 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=115929826&loc=d3e8736-108599 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(1)) -URI http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227 + Details
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