Investments Other (Details) $ in Thousands	12 Months Ended
Dec. 31, 2019 USD ($) period	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Other-Than-Temporary Impairments
Securities held	$ 1,228,040	$ 1,161,862
Material loss threshold, percentage	20.00%
Material loss threshold, number of consecutive quarters \| period	4
Other than Temporary Impairment, Credit Losses Recognized in Earnings
Credit losses on fixed maturity securities, beginning of period	$ 844	892	$ 1,094
Add: credit losses on OTTI not previously recognized	889	228	256
Less: credit losses on securities sold	(1,064)	(276)	(458)
Credit losses on fixed maturity securities, end of period	669	$ 844	$ 892
Amounts included in accumulated other comprehensive income related to OTTI securities	0
Short-term Investments	0
Subprime mortgage debt securities
Other-Than-Temporary Impairments
Securities held	$ 0

The minimum percentage that serves as the threshold for designation of an investment loss as material.

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The minimum number of consecutive quarters that serves as the threshold for designation of an investment loss as material.

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Accumulated other comprehensive loss related to portion of other than temporary impairment (OTTI) due to factors other than credit losses on debt securities categorized as available-for-sale that an entity does not intend to sell and which it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis of the debt security. The amount represented by this item is net of tax, as applicable.

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Amount of investment in marketable security.

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This item represents an increase to the cumulative amount of credit losses recognized in earnings for an other than temporary impairment (OTTI) of a debt security held for which no such other than temporary impairment (OTTI) was previously recognized.

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The cumulative amount of credit losses recognized in earnings related to debt securities held for which a portion of an other than temporary impairment (OTTI) was recognized in other comprehensive income (a component of shareholders' equity).

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This item represents reductions in the cumulative amount of credit losses recognized in earnings for an other than temporary impairment (OTTI) of a debt security because of the sale of impaired securities during the period.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of investments including trading securities, available-for-sale securities, held-to-maturity securities, and short-term investments classified as other and current.

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