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Borrowings Borrowings - Phantom (Details) | Jul. 31, 2018 | Mar. 31, 2018 | Nov. 30, 2017 | Feb. 28, 2017
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Issuance 2017-A |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Derivative, Basis Spread on Variable Rate |  |  |  | 0.93%
Issuance 2017-B |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Derivative, Basis Spread on Variable Rate |  |  | 0.80% |
Issuance 2018-A |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Derivative, Basis Spread on Variable Rate |  | 7.80% |  |
Issuance 2018-B |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Derivative, Basis Spread on Variable Rate | 7.60% |  |  |
Issuance 2018-C |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Derivative, Basis Spread on Variable Rate | 7.70% |  |  |

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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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