Federal Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018
Tax Credit Carryforward [Line Items]
Income taxes paid or refunded, net	$ 58,940	$ 15,064
Income tax examination description	American National’s federal income tax returns for years 2016 to 2018 are subject to examination by the Internal Revenue Service.
AMT Credit Carryforward
Tax Credit Carryforward [Line Items]
Tax credit carryforward	$ 575

A brief description of status of the tax examination, significant findings to date, and the entity's position with respect to the findings.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (d)(2)
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The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income, net of any cash received during the current period as refunds for the overpayment of taxes.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 2
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The amount of the tax credit carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

+ References

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-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
-Paragraph 3
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Line items represent financial 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.

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No definition available.

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