Investments (Net Realized And Unrealized Gains On Fixed Maturity Investments And Net Other Than Temporary Impairments) (Details) (USD $) In Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Investments
Gross realized gains	$ 38,054	$ 30,959	$ 64,046	$ 108,560
Gross realized losses	(6,099)	(748)	(22,872)	(11,880)
Net realized gains on fixed maturity investments	31,955	30,211	41,174	96,680
Net unrealized (losses) gains on fixed maturity investments trading	(13,007)	62,131	7,963	113,913
Net unrealized losses on equity investments trading	(1,965)		(2,389)
Net realized and unrealized gains on investments	16,983	92,342	46,748	210,593
Total other-than-temporary impairments	(498)		(498)	(831)
Portion recognized in other comprehensive income, before taxes	49		49	2
Net other-than-temporary impairments	$ (449)		$ (449)	$ (829)

This item represents the total unrealized gain (loss) included in earnings for the period as a result of holding investments in the common stock of public entities and categorized as trading.

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This item represents the gross profit realized on the sale of debt securities categorized as trading or available for sale.

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This item represents the gross losses realized on the sale of debt securities categorized as trading or available for sale.

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Trading And Available For Sale Securities Realized Gains Losses Net

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This item represents the net total realized and unrealized gain (loss) included in earnings for the period as a result of selling or holding marketable securities categorized as trading, available-for-sale, or held-to-maturity, including the unrealized holding gain (loss) of held-to-maturity securities transferred to the trading security category and the cumulative unrealized gain (loss) which was included in other comprehensive income (a separate component of shareholders' equity) for available-for-sale securities transferred to trading securities during the period. Additionally, this item would include any gains (losses) realized during the period from the sale of investments accounted for under the cost method of accounting and losses recognized for other than temporary impairments (OTTI) of the subject investments.

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The amount by which the fair value of an investment is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

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The amount of other than temporary impairment (OTTI) loss on a debt security, categorized as Available-for-sale, related to factors other than credit losses when the entity does not intend to sell the security and it is not more likely than not that the entity will be required to sell the security before recovery of its amortized cost basis. This amount, which includes the portion attributable to the noncontrolling interest, if any, is a portion of the deduction from the total impairment losses of investments (before taxes) presented on the income statement; this amount is also referred to as the amount incurred by the reporting entity or the consolidated entity.

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The amount of other than temporary impairment losses on investments in debt and equity securities categorized as Available-for-sale which have been recognized in earnings during the period. Such impairment losses consist of other than temporary impairments (OTTI) on equity securities, credit losses on investments in debt securities, and when the entity intends to sell an impaired debt security or it is more likely than not that the entity will be required to sell the impaired debt security before recovery of its amortized cost basis.

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The increase (decrease) resulting in a gain from the difference between the fair value and the carrying value, or in the comparative fair values, of trading securities held at each balance sheet date, that was included in earnings for the period.

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