Segment Reporting (Schedule Of Underwriting Results For Operating Segments To Income (Loss) Before Taxes) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Segment Reporting [Abstract]
Underwriting gain (loss)	$ 67,108us-gaap_UnderwritingIncomeLoss	$ 77,054us-gaap_UnderwritingIncomeLoss
Net investment income	72,581us-gaap_NetInvestmentIncome	63,787us-gaap_NetInvestmentIncome
Net realized capital gains (losses)	21,296us-gaap_RealizedInvestmentGainsLosses	(4,050)us-gaap_RealizedInvestmentGainsLosses
Corporate expense	(1,609)us-gaap_GeneralAndAdministrativeExpense	(1,302)us-gaap_GeneralAndAdministrativeExpense
Interest, fee and bond issue cost amortization expense	(8,859)us-gaap_InterestExpense	(7,436)us-gaap_InterestExpense
Other income (expense)	15,833us-gaap_OtherCostAndExpenseOperating	(3,055)us-gaap_OtherCostAndExpenseOperating
INCOME (LOSS) BEFORE TAXES	$ 166,350	$ 124,998

The aggregate total of expenses of managing and administering the affairs of an entity, including affiliates of the reporting entity, which are not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

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- Definition

Sum of operating profit and nonoperating income or expense before Income or Loss from equity method investments, income taxes, extraordinary items, and noncontrolling interest.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(h)(1)(i))

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- Definition

Amount of the cost of borrowed funds accounted for as interest expense.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391

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-Name Accounting Standards Codification

-Topic 942

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-04.9)

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 9

-Article 9

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- Definition

Amount, after investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 16

-Article 12

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-04.2)

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-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 2

-Article 7

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- Definition

The total amount of other operating cost and expense items that are associated with the entity's normal revenue producing operation.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.3)

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-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 3

-Article 5

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- Definition

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.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-04.3(a))

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-Name Accounting Standards Codification

-Topic 944

-SubTopic 325

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-Publisher SEC

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-Number 210

-Section 04

-Paragraph 3

-Subparagraph a

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- Definition

The difference between the price paid by the public and the contract price less the related expenses. A broker-dealer may underwrite a security offering by contracting to buy the issue either at a fixed price or a price based on selling the offering on a best-effort basis.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-04.13(b))

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-Name Accounting Standards Codification

-Topic 940

-SubTopic 605

-Section 05

-Paragraph 1

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