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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 | Jun. 30, 2017 | Dec. 31, 2016
--- | --- | ---
Carrying Value |  | $ 116,411 | $ 102,397
Other Investments [Member] |  |  |
Carrying Value |  | 116,411 | 102,397
Remaining Commitment |  | 164,655 | 143,686
Maximum Exposure to Loss | [1] | 281,066 | 246,083
Alternative Investments [Member] |  |  |
Carrying Value |  | 97,670 | 83,814
Remaining Commitment |  | 164,655 | 140,286
Maximum Exposure to Loss | [1] | 262,325 | 224,100
Private Equity [Member] | Alternative Investments [Member] |  |  |
Carrying Value |  | 46,945 | 41,135
Remaining Commitment |  | 76,027 | 76,774
Maximum Exposure to Loss | [1] | 122,972 | 117,909
Private Credit [Member] | Alternative Investments [Member] |  |  |
Carrying Value |  | 29,942 | 28,193
Remaining Commitment |  | 57,391 | 40,613
Maximum Exposure to Loss | [1] | 87,333 | 68,806
Real Assets [Member] | Alternative Investments [Member] |  |  |
Carrying Value |  | 20,783 | 14,486
Remaining Commitment |  | 31,237 | 22,899
Maximum Exposure to Loss | [1] | 52,020 | 37,385
Other Securities [Member] |  |  |
Carrying Value |  | 18,741 | 18,583
Remaining Commitment |  | 0 | 3,400
Maximum Exposure to Loss | [1] | $ 18,741 | $ 21,983
[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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