Investments (Summary Of Components Of Net Realized Capital Gains (Losses)) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Schedule of Available-for-sale Securities [Line Items]
Other-than-temporary impairments	$ (2,290)	$ (35)
Other invested assets	929,729		$ 882,647
Total net realized capital gains (losses)	135,056	(60,201)
Fixed Maturity Securities [Member] \| Market Value [Member]
Schedule of Available-for-sale Securities [Line Items]
Other-than-temporary impairments	(2,290)	(35)
Gains (losses) from sales	3,426	6,130
Fixed Maturity Securities [Member] \| Fair Value [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains (losses) from sales		(14)
Gains (losses) from fair value adjustments	13
Equity Securities [Member] \| Fair Value [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains (losses) from sales	5,044	(2,481)
Gains (losses) from fair value adjustments	77,846	(27,014)
Other invested assets	396	3
Other Invested Assets [Member] \| Fair Value [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains (losses) from fair value adjustments	50,627	(36,789)
Short-Term Investments [Member] \| Fair Value [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains (losses) from sales	$ (6)	$ (1)

This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

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