Commitments and Contingencies (Narrative) (Details) - USD ($) $ in Millions  | 
Nov. 30, 2018  | 
May 31, 2018  | 
|---|---|---|
| Commitments and Contingencies [Abstract] | ||
| Commitments to purchase capital assets | $ 4.4 | $ 6.7 | 
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- References No definition available. 
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- Definition Amount of contractual obligation, including but not limited to, long-term debt, capital lease obligations, operating lease obligations, purchase obligations, and other commitments. No definition available. 
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