Summary of Significant Accounting Policies - Guaranteed Minimum Death Benefit (Details) - Guarantee Minimum Death Benefit - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Net Amount at Risk by Product and Guarantee [Line Items]
GMDB reserve	$ 258	$ 152
Aggregate in-the-money death benefits under the GMDB provision	$ 48,083	$ 28,345
Variable annuity contract value distribution based on GMDB feature:
No guarantee	30.00%	29.00%
Return of premium guarantee	65.00%	65.00%
Guarantee of premium roll-up at an annual rate of 3% or 5%	5.00%	6.00%
Total	100.00%	100.00%

Aggregate in money death benefits under guaranteed minimum death benefit reserve provision.

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- Definition

Guaranteed minimum death benefit reserve.

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- Definition

Variable annuity contract value distribution guarantee of premium roll up annual interest rate.

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- Definition

Variable annuity contract value distribution no guarantee percent.

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Variable annuity contract value distribution percent.

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- Definition

Variable annuity contract value distribution return of premium guarantee percent.

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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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