Investments - Summary of Sources of Collateral Received and Various Investment Agreement in which Collateral Pledged (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Investment [Line Items]
Fair Value Of Securities Deposited With Governmental Authorities	$ 5,974	$ 5,872
Securities Held To Collateralize And Fund Repayment Of Debt Issued Through Resecuritization Transaction Fair Value	346,212	360,759
Successor [Member] \| Cash and Securities Pledged Directly from Investment Portfolio [Member]
Investment [Line Items]
Fair Value of Cash and Underlying Securities	120,645	291,545
Fair Value of Cash and Securities Pledged to Investment and Repurchase Agreement Counterparties	0	88,940
Fair Value of Cash and Securities Pledged to Derivative Counterparties	$ 120,645	$ 202,605

Fair value of cash and securities pledged to derivative counterparties.

No definition available.

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- Definition

Fair value of cash and securities pledged to investment and repurchase agreement counterparties.

+ References

No definition available.

+ Details

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- Definition

Total fair value of cash and underlying securities pledged.

+ References

No definition available.

+ Details

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- Definition

Fair value of securities deposited with governmental authorities.

+ References

No definition available.

+ Details

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- Definition

Fair Value of securities held to collateralize and fund repayment of debt issued through a resecuritization transaction.

+ 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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- Details

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