Investments (Net Realized and Unrealized Investment Gains and (Losses)) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Gain (Loss) on Securities [Line Items]
Gross gains on sales	$ 7,151	$ 2,975	$ 12,906	$ 15,129
Gross losses on sales	(2,505)	(2,402)	(8,787)	(7,841)
Debt and Equity Securities, Realized Gain (Loss)	4,646	573	4,119	7,288
Net unrealized gains (losses) on equity securities	(3,111)	4,338	15,830	(7,098)
Losses on securities for which we have the intent to sell	(30)	(44)	(483)	(16,259)
Net realized and unrealized investment gains (losses)	177	7,721	15,353	(24,296)
Available-for-sale Securities [Member]
Gain (Loss) on Securities [Line Items]
Net credit loss benefit (expense) on fixed maturities	(1,334)	2,853	(4,059)	(8,011)
Held-to-maturity Securities [Member]
Gain (Loss) on Securities [Line Items]
Net credit loss benefit (expense) on fixed maturities	6	3	(54)	4
Commercial Mortgage Loans [Member]
Gain (Loss) on Securities [Line Items]
Net credit loss benefit (expense) on fixed maturities	$ 0	$ (2)	$ 0	$ (220)

The credit loss expensed during the period on investment portfolio.

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This item represents the gross gain realized on sales of debt and equity investments.

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This item represents the gross losses realized on the sale of debt and equity investments.

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Losses on investment securities for which we have the intent to sell

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Amount of realized gain (loss) on investment in debt and equity securities.

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Amount of unrealized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-SubTopic 220
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Amount of realized and unrealized gain (loss) on investment.

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