Basis of Presentation - Investment Contract and Life Policy Reserves (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Investment contract reserves	$ 4,545,232	$ 4,452,972
Life policy reserves	1,145,457	1,120,763
Total	$ 5,690,689	$ 5,573,735

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

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Amount of accrued obligation to policyholders that relates to insured events under individual and group annuities and supplementary insurance contracts.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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-Topic 944
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Amount of accrued obligation to policyholders that relates to insured events under long-term life insurance contracts.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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