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Investments - Summary of Sources of Collateral Received and Various Investment Agreement in which Collateral Pledged (Detail) - USD ($) $ in Thousands | Mar. 31, 2019 | Dec. 31, 2018
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Investment [Line Items] |  |
Fair Value Of Securities Deposited With Governmental Authorities | $ 6,046 | $ 5,975
Fair Value of Securities Deposited in Connection wtih Letter of Credit | 1,403 |
Market Value of Secured Note Collateral | 207,759 | 209,983
Investment Portfolio [Member] |  |
Investment [Line Items] |  |
Fair Value of Cash and Securities Pledged to Derivative Counterparties | $ 111,014 | $ 102,904

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- Definition Fair value of cash and securities pledged to derivative counterparties. + 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 Deposited in Connection wtih Letter of Credit + 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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