Investments - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Investment Holdings [Line Items]
Investment grade rating	81.20%
Limited partnership interests	$ 448,996	$ 383,717
Fair value of issued securities	6,345,290	5,791,676
FHLB funding agreements	644,500	545,000
FHLB of Chicago
Investment Holdings [Line Items]
Fair value of issued securities	707,300	594,200
Governmental agencies as required by law in various states
Investment Holdings [Line Items]
Fair value of issued securities	$ 26,900	$ 26,000

Represents the federal home loan bank funding agreements.

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Percentage of fair value of fixed maturity and equity securities with a gross unrealized loss having an investment grade rating at period end.

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- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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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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Amount of investment in equity method investee and investment in and advance to affiliate.

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