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Investments (Other Investment Portfolio by Strategy and the Remaining Commitment Amount Associated With Each Strategy) (Details) - USD ($) $ in Thousands | Dec. 31, 2015 | Dec. 31, 2014
--- | --- | ---
Carrying Value | $ 77,842 | $ 99,203
Alternative Investments [Member] |  |
Carrying Value | 67,834 | 92,968
Remaining Commitment | 71,153 |
Other Investment Portfolio [Member] |  |
Carrying Value | 77,842 | 99,203
Remaining Commitment | 74,353 |
Secondary Private Equity [Member] | Alternative Investments [Member] |  |
Carrying Value | 35,088 | 48,538
Remaining Commitment | 30,204 |
Private Equity [Member] | Alternative Investments [Member] |  |
Carrying Value | 13,246 | 18,533
Remaining Commitment | 15,129 |
Energy Power Generation [Member] | Alternative Investments [Member] |  |
Carrying Value | 19,500 | 25,897
Remaining Commitment | 25,820 |
Other Securities [Member] |  |
Carrying Value | 10,008 | $ 6,235
Remaining Commitment | $ 3,200 |

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- Definition Other investments not otherwise specified in the taxonomy. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.12) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.1(f,g)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
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