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Derivative Financial Instruments (Schedule Of Derivative Gains And Losses In The Consolidated Statements Of Operations) (Details) - Not Designated as Hedging Instrument [Member] - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Derivative Financial Instruments [Line Items] |  |  |
(Losses) Gains Recognized in Income | $ 154 | $ 15,379 | $ (3,357)
Total Return Swap [Member] | Net realized investment gains [Member] |  |  |
Derivative Financial Instruments [Line Items] |  |  |
(Losses) Gains Recognized in Income | (2,137) | 11,533 | (6,438)
Equity contracts [Member] | Net realized investment gains [Member] |  |  |
Derivative Financial Instruments [Line Items] |  |  |
(Losses) Gains Recognized in Income | $ 2,291 | $ 3,846 | $ 3,081

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- Definition Derivative Financial Instruments [Line Items] + References No definition available. + Details
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- Definition Amount of increase (decrease) in the fair value of derivatives recognized in the income statement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5618551-113959 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (a),(c),(d),(e) -URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624171-113959 + Details
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