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Investments Realized and Unrealized Gains (Losses) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Gain (Loss) on Securities [Line Items]
Gross gains on sales									$ 18,893	$ 31,910	$ 28,672
Gross losses on sales									(9,745)	(5,195)	(47,647)
Net realized investment gains (losses) on disposals									9,148	26,715	(18,975)
Net unrealized losses on equity securities									7,939	(8,649)	(29,369)
Losses on securities for which we have the intent to sell									(16,266)
OTTI Losses Gross										(3,644)	(6,579)
Net realized and unrealized investment (losses) gain	$ 20,079	$ 7,721	$ 12,649	$ (44,666)	$ (873)	$ (2,183)	$ 4,027	$ 13,451	(4,217)	$ 14,422	$ (54,923)
Available-for-sale Securities [Member]
Credit loss expense on investment portfolio									(5,042)
Held-to-maturity Securities [Member]
Credit loss expense on investment portfolio									$ 4

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The credit loss expensed during the period on investment portfolio.

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

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

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