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Goodwill and Other Intangible Assets - Narrative (Details) - USD ($) $ in Millions | Mar. 31, 2019 | Feb. 26, 2019 | Dec. 31, 2018 | May 18, 2018 | May 11, 2018
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NSM Insurance HoldCo, LLC |  |  |  |  |
Goodwill [Line Items] |  |  |  |  |
Goodwill and intangible assets acquired |  |  |  |  | $ 383.0
Ownership interest (as a percent) | 95.30% |  | 95.50% |  | 95.00%
Fully diluted ownership interest (as a percent) | 84.80% |  | 85.00% |  |
Fresh Insurance Services Group Limited |  |  |  |  |
Goodwill [Line Items] |  |  |  |  |
Goodwill and intangible assets acquired |  |  |  | $ 54.6 |
Ownership interest (as a percent) |  |  |  | 100.00% |
MediaAlpha |  |  |  |  |
Goodwill [Line Items] |  |  |  |  |
Ownership interest (as a percent) |  | 48.30% |  |  |
Fully diluted ownership interest (as a percent) |  | 42.00% |  |  |

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- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571 + Details
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- Definition Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Goodwill and Intangible Assets + References No definition available. + Details
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- Details
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