Consolidated Condensed Schedule Of Investments Consolidated Condensed Schedule of Investments (Cash Equivalents) - Cash Equivalents [Member] - USD ($) shares in Thousands, $ in Thousands |
6 Months Ended | 12 Months Ended | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Jun. 30, 2018 |
Dec. 31, 2017 |
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| Schedule of Investments [Line Items] | |||||||||||||
| Money Market Funds, at Carrying Value | $ 6,833 | [1] | $ 26,500 | [2] | |||||||||
| Money Market Funds, at Cost | $ 6,833 | [1] | $ 26,500 | [2] | |||||||||
| Investment owned as a percentage of equity | 1.11% | [1],[3] | 4.27% | [2],[4] | |||||||||
| Various Money Market Funds [Member] | |||||||||||||
| Schedule of Investments [Line Items] | |||||||||||||
| Money Market Funds, at Carrying Value | $ 6,833 | [1] | $ 26,500 | [2] | |||||||||
| Investment Owned, Balance, Shares | 6,833 | [1] | 26,500 | [2] | |||||||||
| Rate | [2] | 1.17% | |||||||||||
| Various Money Market Funds [Member] | Minimum [Member] | |||||||||||||
| Schedule of Investments [Line Items] | |||||||||||||
| Rate | [1] | 1.80% | |||||||||||
| Various Money Market Funds [Member] | Maximum [Member] | |||||||||||||
| Schedule of Investments [Line Items] | |||||||||||||
| Rate | [1] | 1.81% | |||||||||||
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