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Commitments and Contingencies (Details) $ in Millions, $ in Millions | 3 Months Ended | 6 Months Ended |  |
--- | --- | --- | --- | ---
Mar. 31, 2017 USD ($) | Mar. 31, 2018 CAD ($) | Mar. 31, 2018 USD ($) | Dec. 31, 2014 USD ($)
Loss Contingency, Damages Sought, Value |  | $ 10.0 |  |
Operating Leases |  |  |  |
Product Warranty Expense | $ 9.8 |  |  |
Prior To 1995 [member] |  |  |  |
Walter Energy tax assessment |  |  |  | $ 33.0
IRS-Walter Energy Claim 1 [Member] |  |  |  |
Loss Contingency, Estimate of Possible Loss |  |  | $ 554.3 |
IRS-Walter Energy Claim 1 Priority [Member] |  |  |  |
Loss Contingency, Estimate of Possible Loss |  |  | 229.1 |
IRS-Walter Energy Claim 2 [Member] |  |  |  |
Loss Contingency, Estimate of Possible Loss |  |  | 860.4 |
IRS-Walter Energy Claim 2 Priority [Member] |  |  |  |
Loss Contingency, Estimate of Possible Loss |  |  | $ 535.3 |

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