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Investments (Net Realized and Unrealized Investment Gains and (Losses)) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Gain (Loss) on Securities [Line Items]
Gross gains on sales	$ 3,784	$ 2,197
Gross losses on sales	(12,930)	(13,560)
Net realized (losses) gains on disposals	(9,146)	(11,363)
Net unrealized gains (losses) on equity securities	3,248	(2,154)
Losses on securities for which we have the intent to sell	(304)	(4,797)
Net realized and unrealized investment gains (losses)	3,344	(40,352)
Change in net realized and unrealized investment gains	43,700
Available-for-sale Securities [Member]
Gain (Loss) on Securities [Line Items]
Net credit loss (expense) benefit on fixed income securities	9,529	(22,052)
Held-to-maturity Securities [Member]
Gain (Loss) on Securities [Line Items]
Net credit loss (expense) benefit on fixed income securities	0	14
Commercial Mortgage Loans [Member]
Gain (Loss) on Securities [Line Items]
Net credit loss (expense) benefit on fixed income securities	$ 17	$ 0

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Increase (decrease) in gain (loss) on investments

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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