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v3.10.0.1

Fair Value Measurements - Information about Valuation Inputs for Fixed Income Securities Classified as Level 3 (Detail) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31) |  |
Other Investments | $ 391,217 | $ 431,630
Debt Securities, Available-for-sale | $ 3,546,006 |
Ambac insured Re-remic [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31) |  |
Coupon rate |  | 2.05%
Fair Value Inputs Maturity |  | 7 months 24 days
Yield |  | 0.00%
Asset-backed Securities [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31) |  |
Coupon rate | 5.97% | 5.97%
Fair Value Inputs Maturity | 16 years 3 months 15 days | 17 years 9 days
Yield | 12.00% | 12.00%
Fair Value, Inputs, Level 3 [Member] | Ambac insured Re-remic [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31) |  |
Available-for-sale Securities |  | $ 26,067
Variable Interest Entity, Primary Beneficiary [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31) |  |
Debt Securities, Available-for-sale | $ 2,737,286 | $ 2,914,145
Variable Interest Entity, Primary Beneficiary [Member] | European Transactions [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31) |  |
Coupon rate | 2.20% | 0.40%
Fair Value Inputs Maturity | 18 years 11 months 6 days | 15 years 3 months 11 days
Yield | 3.18% | 4.82%
Real Estate [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31) |  |
Other Investments | $ 16,123 | $ 33,154
Hedge Funds, Multi-strategy [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31) |  |
Other Investments | 0 | 53,054
Interest Rate Contract [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31) |  |
Other Investments | 177,357 | 136,603
Illiquid Investments [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31) |  |
Other Investments | 84,297 | 67,787
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | RMBS Cash Flows Consisting of Deferred Amounts [Domain] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31) |  |
Debt Securities, Available-for-sale, Current | 0 | 709,950
Fair Value, Measurements, Recurring [Member] | Residential Mortgage-Backed Securities [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31) |  |
Debt Securities, Available-for-sale | 258,607 | 2,251,333
Fair Value, Measurements, Recurring [Member] | Residential Mortgage-Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31) |  |
Debt Securities, Available-for-sale | $ 0 | $ 736,017

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- Definition Fair value inputs coupon rate. + References No definition available. + Details
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- Definition Fair value inputs yield. + References No definition available. + Details
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- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109979856&loc=d3e26610-111562 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563 + Details
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