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Basis of Presentation and Significant Accounting Policies FX gain (loss) (Details) - Successor [Member] - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
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Jun. 30, 2017 | Jun. 30, 2016 | Jun. 30, 2017 | Jun. 30, 2016
Foreign Currency Transaction Gain (Loss), before Tax |  |  | $ 14,786 | $ (29,150)
Loss and Loss Reserves [Member] |  |  |  |
Foreign Currency Transaction Gain (Loss), before Tax |  |  | 17,622 | (48,260)
Gain (Loss) on Investments [Member] |  |  |  |
Foreign Currency Transaction Gain (Loss), before Tax | $ (2,349) | $ 10,849 | (432) | 13,632
Premiums Receivable [Member] |  |  |  |
Foreign Currency Transaction Gain (Loss), before Tax |  |  | (981) | 6,945
Unrealized Gains Or (Losses) On Credit Derivative Contracts [Member] |  |  |  |
Foreign Currency Transaction Gain (Loss), before Tax |  |  | $ (920) | $ (502)

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- Definition Amount before tax of foreign currency transaction realized and unrealized gain (loss) recognized in the income statement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6450222&loc=d3e30840-110895 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 20 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=64836518&loc=d3e30700-110894 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=64836518&loc=d3e30690-110894 + Details
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