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Investments (Components Of Net Realized and Unrealized Gains and Losses (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Gain (Loss) on Securities [Line Items]
Total net realized gains on the disposal of securities (excluding OTTI charges)		$ 3,444	$ 4,731
OTTI Charges		(104)	(1,212)
Net realized gains		3,340	3,519
Unrealized gains (losses) recognized in income on equity securities	[1]	10,111	(14,068)
Net realized and unrealized gains (losses)		13,451	(10,549)
Unrealized holding gains (losses) on equity securities		12,000	(5,100)
Unrealized losses on equity securities sold during the period		(1,900)	(9,000)
Fixed Income Securities [Member]
Gain (Loss) on Securities [Line Items]
Net realized (losses) gains on disposals of securities, fixed income securities (excluding OTTI charges)		1,143	(3,335)
Equity Securities [Member]
Gain (Loss) on Securities [Line Items]
Total net realized gains on the disposal of securities (excluding OTTI charges)		2,280	8,069
Short-Term Investments [Member]
Gain (Loss) on Securities [Line Items]
Total net realized gains on the disposal of securities (excluding OTTI charges)		14	(3)
Other Investments [Member]
Gain (Loss) on Securities [Line Items]
Total net realized gains on the disposal of securities (excluding OTTI charges)		$ 7	$ 0
[1] Includes unrealized holding gains (losses) of: (i) $12.0 million in First Quarter 2019 and $(5.1) million in First Quarter 2018 on equity securities remaining in our portfolio as of March 31, 2019 and 2018, respectively; and (ii) $(1.9) million in First Quarter 2019 and $(9.0) million in First Quarter 2018 on equity securities sold in each respective period.

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The unrealized gains (losses) on equity securities sold during the period.

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Aggregate net change in unrealized gains or losses on the equity portfolio recognized in net income for the period.

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

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