Investments (Components Of Net Realized and Unrealized Gains and Losses (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Gain (Loss) on Securities [Line Items]
Net realized gains (losses) on disposals of securities, fixed income securities (excluding OTTI charges)	$ 4,100	$ 3,444
OTTI Charges	31,629	104
Net realized (losses) gains	(27,529)	3,340
Unrealized Gains Losses on Equity Securities	(27,200)
Net realized and unrealized investment (losses) gains	(44,666)	13,451
Total unrealized (losses) gains recognized in income on equity securities	(17,137)	10,111
Increase in net realized and unrealized investment losses	(58,100)
Fixed Income Securities [Member]
Gain (Loss) on Securities [Line Items]
Net realized gains (losses) on disposals of securities, fixed income securities (excluding OTTI charges)	4,276	1,143
Equity Securities [Member]
Gain (Loss) on Securities [Line Items]
Net realized gains (losses) on disposals of securities, fixed income securities (excluding OTTI charges)	(3)	2,280
Short-Term Investments [Member]
Gain (Loss) on Securities [Line Items]
Net realized gains (losses) on disposals of securities, fixed income securities (excluding OTTI charges)	(168)	14
Other Investments [Member]
Gain (Loss) on Securities [Line Items]
Net realized gains (losses) on disposals of securities, fixed income securities (excluding OTTI charges)	(5)	7
OTTI Charges	$ 0	$ 39

Realized and unrealized investment change between the current and prior period.

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Aggregate net change in unrealized gains or losses on the equity portfolio recognized in net income for the current period as compared to the prior period.

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Amount of unrealized and 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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Amount of realized and unrealized gain (loss) on investment.

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Amount of realized gain (loss) on investment in marketable security, excluding other-than-temporary impairment (OTTI).

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The amount of other than temporary impairment (OTTI) losses on equity securities, OTTI related to credit losses on debt securities, and OTTI losses on debt securities when the entity intends to sell the securities or it is more likely than not that the entity will be required to sell the securities before recovery of its amortized cost basis. Additionally, this item includes OTTI losses recognized during the period on investments accounted for under the cost method of accounting.

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The net realized gains or losses on investments during the period, not including gains or losses on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity.

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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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