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Fair Value Measurements - Information about Valuation Inputs for Fixed Income Securities Classified as Level 3 (Detail) - Successor [Member] - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2015 | Dec. 31, 2014
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Available-for-sale Securities | $ 5,334,120 | $ 5,150,018
Corporate Obligations [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Coupon rate |  | 0.345%
Fair Value Inputs Maturity |  | 19 years 1 month 21 days
Yield |  | 4.93%
Fair Value, Inputs, Level 3 [Member] | Corporate Obligations [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Available-for-sale Securities | 0 | $ 3,808
Fair Value, Inputs, Level 3 [Member] | Residential Mortgage-Backed Securities [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Available-for-sale Securities | 488,884 | 194,393
Fair Value, Inputs, Level 3 [Member] | Asset-backed Securities [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Available-for-sale Securities | $ 0 | $ 0
Variable Interest Entity, Primary Beneficiary [Member] | United States Transactions [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Coupon rate | 5.88% | 5.88%
Fair Value Inputs Maturity | 21 years 9 months 22 days | 15 years 10 months 4 days
Yield | 9.14% | 7.37%
Variable Interest Entity, Primary Beneficiary [Member] | European Transactions [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Coupon rate | 1.38% | 0.30%
Fair Value Inputs Maturity | 16 years 4 months 39 days | 21 years 2 months 30 days
Yield | 6.08% | 9.52%
Variable Interest Entity, Primary Beneficiary [Member] | Fair Value, Inputs, Level 3 [Member] | Corporate Obligations [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Available-for-sale Securities | $ 2,588,556 | $ 2,743,050

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- Definition Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=51813488&loc=d3e22054-111558 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=49167202&loc=d3e26610-111562 + Details
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