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Investments - Summary of Fair Value, Including Financial Guarantee, and Weighted-Average Underlying Rating, Excluding Financial Guarantee, of Insured Securities (Phantom) (Detail) - USD ($) $ in Thousands | Jun. 30, 2018 | Dec. 31, 2017
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Ambac UK [Member] |  |
Investment [Line Items] |  |
Corporate and Asset Backed Securities Fair Value Disclosure | $ 172,531 | $ 170,280

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- Definition Corporate and Asset Backed Securities Fair Value Disclosure + References No definition available. + Details
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- Definition Line items represent reporting 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 Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 12 -Section 12 -Sentence Column A + Details
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- Details
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