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Goodwill and Other Intangible Assets - Changes In Intangible Assets and Goodwill (Details) - USD ($) $ in Millions |  | 3 Months Ended | 9 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | --- | ---
Aug. 04, 2016 | Mar. 31, 2016 | Sep. 30, 2017 | Sep. 30, 2016 | Jun. 30, 2017 | Dec. 31, 2016 | Jun. 30, 2016 | Dec. 31, 2015
Acquired Finite-Lived Intangible Assets [Line Items] |  |  |  |  |  |  |  |
Payments to acquire businesses and interest in affiliates |  |  | $ 0.0 | $ 13.7 |  |  |  |
Assets |  |  | 3,637.1 |  |  | $ 6,520.2 |  |
Goodwill |  |  | 25.9 | $ 25.9 | $ 25.9 | 25.9 | $ 18.3 | $ 18.6
Liabilities |  |  | $ 299.9 |  |  | $ 2,804.2 |  |
Oversee.net |  |  |  |  |  |  |  |
Acquired Finite-Lived Intangible Assets [Line Items] |  |  |  |  |  |  |  |
Payments to acquire businesses and interest in affiliates |  | $ 3.9 |  |  |  |  |  |
Buzzmove |  |  |  |  |  |  |  |
Acquired Finite-Lived Intangible Assets [Line Items] |  |  |  |  |  |  |  |
Ownership interest (as a percent) | 70.90% |  | 77.10% |  |  |  |  |
Assets | $ 11.5 |  |  |  |  |  |  |
Goodwill | 7.6 |  |  |  |  |  |  |
Intangible Assets, Net (Excluding Goodwill) | 1.1 |  |  |  |  |  |  |
Liabilities | 0.1 |  |  |  |  |  |  |
United Kingdom, Pounds | Buzzmove |  |  |  |  |  |  |  |
Acquired Finite-Lived Intangible Assets [Line Items] |  |  |  |  |  |  |  |
Acquisition of subsidiary | 6.1 |  |  |  |  |  |  |
United States of America, Dollars | Buzzmove |  |  |  |  |  |  |  |
Acquired Finite-Lived Intangible Assets [Line Items] |  |  |  |  |  |  |  |
Acquisition of subsidiary | $ 8.1 |  |  |  |  |  |  |

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- Definition Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(12)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(11)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
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