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Long- Term Debt to Affiliated Trust Long-Term Debt to Affiliated Trust (Tables) | 6 Months Ended
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Jun. 30, 2017
Long-Term Debt to Affiliated Trust [Abstract] |
Schedule Of Distribution Rates Paid [Table Text Block] | The distribution rates paid were as follows during the six months ended June 30, 2017 and the year ended December 31, 2016:
| June 30, |  | December 31,
| 2017 |  | 2016
Low distribution rate | 1.81 | % |  | 1.29 | %
High distribution rate | 2.08 | % |  | 1.81 | %
Distribution rate at the end of the period | 2.08 | % |  | 1.81 | %

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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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