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Investments (Other Investment Portfolio by Strategy and the Remaining Commitment Amount and Maximum Exposure to Loss Associated With Each Strategy) (Details) - USD ($) $ in Thousands | Sep. 30, 2016 | Dec. 31, 2015
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Carrying Value |  | $ 88,512 | $ 77,842
Other Investments [Member] |  |  |
Carrying Value |  | 88,512 | 77,842
Remaining Commitment |  | 134,089 | 74,353
Maximum Exposure to Loss | [1] | 222,601 | 152,195
Alternative Investments [Member] |  |  |
Carrying Value |  | 78,482 | 67,834
Remaining Commitment |  | 111,478 | 71,153
Maximum Exposure to Loss | [1] | 189,960 | 138,987
Private Equity [Member] | Alternative Investments [Member] |  |  |
Carrying Value |  | 35,444 | 35,088
Remaining Commitment |  | 57,793 | 30,204
Maximum Exposure to Loss | [1] | 93,237 | 65,292
Private Credit [Member] | Alternative Investments [Member] |  |  |
Carrying Value |  | 27,709 | 13,246
Remaining Commitment |  | 30,763 | 15,129
Maximum Exposure to Loss | [1] | 58,472 | 28,375
Real Assets [Member] | Alternative Investments [Member] |  |  |
Carrying Value |  | 15,329 | 19,500
Remaining Commitment |  | 22,922 | 25,820
Maximum Exposure to Loss | [1] | 38,251 | 45,320
Other Securities [Member] |  |  |
Carrying Value |  | 10,030 | 10,008
Remaining Commitment |  | 22,611 | 3,200
Maximum Exposure to Loss | [1] | $ 32,641 | $ 13,208
[1] | The maximum exposure to loss includes both the carry value of these investments and the related unfunded commitments. In addition, tax credits that have been previously recognized in Other securities are subject to the risk of recapture, which we do not consider significant.

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