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Financial Instruments and Risk Management (Fuel Option Contracts) (Details) - Fuel Options [Member] - Commodity price risk [member] $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) $ / gal
Disclosure of detailed information about hedged items [line items]
Gains (losses) on change in fair value of derivatives | $	$ (0.1)
Bottom of range [member]
Disclosure of detailed information about hedged items [line items]
Average price of hedging instrument	1.00
Top of range [member]
Disclosure of detailed information about hedged items [line items]
Average price of hedging instrument	1.50

X

- Definition

The average price of a hedging instrument. [Refer: Hedging instruments [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-IssueDate 2020-01-01
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- Definition

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

+ References

No definition available.

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- Definition

The gains (losses) resulting from change in the fair value of derivatives recognised in profit or loss. [Refer: Derivatives [member]]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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-IssueDate 2020-01-01
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