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Goodwill and intangibles - Additional Information (Details) - USD ($) $ in Millions |  | 9 Months Ended
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Sep. 12, 2017 | Oct. 28, 2017
Finite-Lived Intangible Assets [Line Items] |  |
Goodwilll, acquired during period |  | $ 348.5
R2Net Inc. |  |
Finite-Lived Intangible Assets [Line Items] |  |
Goodwilll, acquired during period | $ 348.5 |

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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition 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. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267 + Details
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- Details
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