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Contingencies (Details) $ in Thousands | 12 Months Ended |
--- | --- | ---
Apr. 30, 2017 USD ($) lawsuit state | Apr. 30, 2016 USD ($)
Loss Contingency [Abstract] |  |
Accrued environmental liability | $ 283 | $ 341
Loss Contingencies |  |
Annual stop loss limit | 1,000 |
Letters of credit outstanding | 21,126 | 20,115
Investments In escrow for insurance | $ 223 |
Number of states that require partial self-insurance | state | 1 |
Self-insurance reserves | $ 37,984 | $ 35,535
Motor Fuel Temperature Sales Practices (Hot Fuel) |  |
Loss Contingencies |  |
Number of lawsuits | lawsuit | 4 |

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