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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 | Mar. 31, 2019 | Dec. 31, 2018
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Carrying Value |  | $ 176,225 | $ 178,938
Other Investments [Member] |  |  |
Carrying Value |  | 176,225 | 178,938
Remaining Commitment |  | 217,261 | 202,270
Maximum Exposure to Loss | [1] | 393,486 | 381,208
Alternative Investments [Member] |  |  |
Carrying Value |  | 151,733 | 153,896
Remaining Commitment |  | 217,261 | 202,270
Maximum Exposure to Loss | [1] | 368,994 | 356,166
Private Equity [Member] | Alternative Investments [Member] |  |  |
Carrying Value |  | 92,371 | 84,352
Remaining Commitment |  | 101,297 | 93,688
Maximum Exposure to Loss | [1] | 193,668 | 178,040
Private Credit [Member] | Alternative Investments [Member] |  |  |
Carrying Value |  | 30,518 | 41,682
Remaining Commitment |  | 90,812 | 81,453
Maximum Exposure to Loss | [1] | 121,330 | 123,135
Real Assets [Member] | Alternative Investments [Member] |  |  |
Carrying Value |  | 28,844 | 27,862
Remaining Commitment |  | 25,152 | 27,129
Maximum Exposure to Loss | [1] | 53,996 | 54,991
Other Securities [Member] |  |  |
Carrying Value |  | 24,492 | 25,042
Remaining Commitment |  | 0 | 0
Maximum Exposure to Loss | [1] | $ 24,492 | $ 25,042
[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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- Definition The reporting entity's maximum amount of exposure to loss as a result of its involvement with the Variable Interest Entity (VIE). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=108788376&loc=d3e5747-111685 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 50 -Paragraph 4 -Subparagraph b -URI http://asc.fasb.org/extlink&oid=108788376&loc=d3e5728-111685 + Details
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