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Long- Term Debt to Affiliated Trust Long-Term Debt to Affiliated Trust (Tables) | 3 Months Ended
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Mar. 31, 2018
Long-Term Debt to Affiliated Trust [Abstract] |
Schedule Of Distribution Rates Paid [Table Text Block] | The distribution rates paid were as follows during the three months ended March 31, 2018 and the year ended December 31, 2017:
| March 31, |  | December 31,
| 2018 |  | 2017
Low distribution rate | 2.36 | % |  | 1.81 | %
High distribution rate | 2.88 | % |  | 2.36 | %
Distribution rate at the end of the period | 2.88 | % |  | 2.36 | %

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- Definition Long-Term Debt to Affiliated Trust [Abstract] + References No definition available. + Details
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- Definition Schedule Of Distribution Rates Paid [Table Text Block] + References No definition available. + Details
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