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Goodwill and Other Intangible Assets - Goodwill and Intangible Assets (Details) - USD ($) $ in Millions | Sep. 30, 2017 | Jun. 30, 2017 | Dec. 31, 2016 | Sep. 30, 2016 | Jun. 30, 2016 | Dec. 31, 2015
--- | --- | --- | --- | --- | --- | ---
Acquired Finite-Lived Intangible Assets [Line Items] |  |  |  |  |  |
Goodwill | $ 25.9 | $ 25.9 | $ 25.9 | $ 25.9 | $ 18.3 | $ 18.6
Goodwill and other intangible assets | 37.8 | 40.3 | 45.2 | 47.7 | 41.6 | 45.5
MediaAlpha |  |  |  |  |  |
Acquired Finite-Lived Intangible Assets [Line Items] |  |  |  |  |  |
Goodwill | 18.3 |  | 18.3 |  |  |
Buzzmove |  |  |  |  |  |
Acquired Finite-Lived Intangible Assets [Line Items] |  |  |  |  |  |
Goodwill | 7.6 |  | 7.6 |  |  |
Other Intangible Assets |  |  |  |  |  |
Acquired Finite-Lived Intangible Assets [Line Items] |  |  |  |  |  |
Intangible Assets, Net (Excluding Goodwill) | 11.9 | $ 14.4 | 19.3 | $ 21.8 | $ 23.3 | $ 26.9
Other Intangible Assets | MediaAlpha |  |  |  |  |  |
Acquired Finite-Lived Intangible Assets [Line Items] |  |  |  |  |  |
Intangible Assets, Net (Excluding Goodwill) | 11.0 |  | 18.3 |  |  |
Other Intangible Assets | Buzzmove |  |  |  |  |  |
Acquired Finite-Lived Intangible Assets [Line Items] |  |  |  |  |  |
Intangible Assets, Net (Excluding Goodwill) | 0.9 |  | 1.0 |  |  |
Discontinued Operations, Held-for-sale |  |  |  |  |  |
Acquired Finite-Lived Intangible Assets [Line Items] |  |  |  |  |  |
Goodwill and other intangible assets | 0.0 |  | 1.2 |  |  |
Non-controlling interest |  |  |  |  |  |
Acquired Finite-Lived Intangible Assets [Line Items] |  |  |  |  |  |
Goodwill and other intangible assets | (13.7) |  | (17.1) |  |  |
Total |  |  |  |  |  |
Acquired Finite-Lived Intangible Assets [Line Items] |  |  |  |  |  |
Goodwill and other intangible assets | $ 24.1 |  | $ 29.3 |  |  |

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- Definition 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. + 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 (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=64834752&loc=SL49117168-202975 + Details
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- Definition Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16212-109274 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph ((a)(1),(b)) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
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