Investments - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Investment Holdings [Line Items]
Investment grade rating	95.50%
Fair value of issued securities	$ 7,515,318	$ 7,724,075
FHLB funding agreements	675,000	625,000
Limited partnership interests	328,516	247,266
Governmental agencies as required by law in various states
Investment Holdings [Line Items]
Fair value of issued securities	17,695	17,985
FHLB of Chicago
Investment Holdings [Line Items]
Fair value of issued securities	$ 740,016	$ 686,790

Represents the federal home loan bank funding agreements.

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- Definition

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

+ References

No definition available.

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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).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (b)
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- Definition

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.

+ References

No definition available.

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- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
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