Investments (Summary Of Aggregate Market Value And Gross Unrealized Depreciation Of Fixed Maturity And Equity Securities, By Contractual Maturity) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Market Value, Total	$ 1,414,865	$ 2,571,006
Available-for-sale Securities, Gross Unrealized Depreciation, Total	(60,629)	(100,332)
Fixed Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities, Less than 12 months, Market Value	894,404	1,925,177
Available for sale securities, Less than 12 months, Gross Unrealized Depreciation	(26,847)	(62,697)
Available for sale securities, Greater than 12 months, Market Value	520,461	645,829
Available for sale securities, Greater than 12 months, Gross Unrealized Depreciation	(33,782)	(37,635)
Available-for-sale Securities, Market Value, Total	1,414,865	2,571,006
Available-for-sale Securities, Gross Unrealized Depreciation, Total	(60,629)	(100,332)
Due In One Year Or Less [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities, Less than 12 months, Market Value	39,889	21,780
Available for sale securities, Less than 12 months, Gross Unrealized Depreciation	(183)	(1,577)
Available for sale securities, Greater than 12 months, Market Value	32,078	12,212
Available for sale securities, Greater than 12 months, Gross Unrealized Depreciation	(3,841)	(1,171)
Available-for-sale Securities, Market Value, Total	71,967	33,992
Available-for-sale Securities, Gross Unrealized Depreciation, Total	(4,024)	(2,748)
Due In One Year Through Five Years [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities, Less than 12 months, Market Value	422,494	1,023,437
Available for sale securities, Less than 12 months, Gross Unrealized Depreciation	(9,573)	(23,255)
Available for sale securities, Greater than 12 months, Market Value	276,367	347,203
Available for sale securities, Greater than 12 months, Gross Unrealized Depreciation	(17,598)	(21,582)
Available-for-sale Securities, Market Value, Total	698,861	1,370,640
Available-for-sale Securities, Gross Unrealized Depreciation, Total	(27,171)	(44,837)
Due In Five Years Through Ten Years [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities, Less than 12 months, Market Value	265,716	394,978
Available for sale securities, Less than 12 months, Gross Unrealized Depreciation	(14,274)	(31,423)
Available for sale securities, Greater than 12 months, Market Value	60,641	99,335
Available for sale securities, Greater than 12 months, Gross Unrealized Depreciation	(10,681)	(10,131)
Available-for-sale Securities, Market Value, Total	326,357	494,313
Available-for-sale Securities, Gross Unrealized Depreciation, Total	(24,955)	(41,554)
Due After Ten Years [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities, Less than 12 months, Market Value	28,084	35,708
Available for sale securities, Less than 12 months, Gross Unrealized Depreciation	(1,651)	(2,046)
Available for sale securities, Greater than 12 months, Market Value	5,339	8,936
Available for sale securities, Greater than 12 months, Gross Unrealized Depreciation	(428)	(970)
Available-for-sale Securities, Market Value, Total	33,423	44,644
Available-for-sale Securities, Gross Unrealized Depreciation, Total	(2,079)	(3,016)
Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities, Less than 12 months, Market Value	20,482	102,506
Available for sale securities, Less than 12 months, Gross Unrealized Depreciation	(77)	(791)
Available for sale securities, Greater than 12 months, Market Value	31,533	28,048
Available for sale securities, Greater than 12 months, Gross Unrealized Depreciation	(210)	(272)
Available-for-sale Securities, Market Value, Total	52,015	130,554
Available-for-sale Securities, Gross Unrealized Depreciation, Total	(287)	(1,063)
Collateralized Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities, Less than 12 months, Market Value	117,739	346,768
Available for sale securities, Less than 12 months, Gross Unrealized Depreciation	(1,089)	(3,605)
Available for sale securities, Greater than 12 months, Market Value	114,503	150,095
Available for sale securities, Greater than 12 months, Gross Unrealized Depreciation	(1,024)	(3,509)
Available-for-sale Securities, Market Value, Total	232,242	496,863
Available-for-sale Securities, Gross Unrealized Depreciation, Total	$ (2,113)	$ (7,114)

Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for twelve months or longer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27290-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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-Section 50
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-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27337-111563

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Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale in a continuous loss position.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27337-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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-Topic 320
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-Section 50
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-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27337-111563

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27290-111563

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