Related Party Transactions - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Related Party Transaction [Line Items]
Operating expenses, including compensation, allocated by Allstate Insurance Company	$ 46,300	$ 40,000	$ 39,000
Reserve for annuities issued	2,348,966	2,140,888
Ceded premium related to structured settlement annuities	11,481	11,788	12,362
Maximum amount of loans Corporation will have outstanding to all eligible subsidiaries at any given point in time	1,000,000
Allstate Insurance Company ("AIC")
Related Party Transaction [Line Items]
Reserve for annuities issued	1,420,000	1,420,000
Allstate Distributors Services, LLC
Related Party Transaction [Line Items]
Broker-Dealer agreement, Promotion and marketing expense	6	4	23
Allstate Financial Services, LLC
Related Party Transaction [Line Items]
Broker-Dealer agreement, Commission and other distribution expenses	259	450	233
Allstate Life Insurance Company
Related Party Transaction [Line Items]
Reserve for annuities issued	591,100	607,300
Ceded premium related to structured settlement annuities	3,500	3,400	$ 3,400
Carrying value of structured settlement reinsurance treaty	$ 166,300	$ 109,600

Related Party Transaction Maximum Limit Of Borrowings

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- Definition

Amount of earned premiums ceded to other entities.

+ References

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Costs of sales and operating expenses for the period incurred from transactions with related parties.

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Fair value, after offset of derivative liability, of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, before offset against an obligation to return collateral under a master netting arrangement. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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- Definition

Amount of accrued obligation to policyholders that relates to insured events for long-duration contracts.

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The total expense recognized in the period for promotion, public relations, and brand or product advertising.

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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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