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Financial Instruments and Risk Management (Revolving Credit Facility) (Details) | Sep. 21, 2017 USD ($) | Mar. 31, 2020 USD ($)
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Revolving Credit Facility [Member] |  |
Debt and Financing Obligations [Line Items] |  |
Borrowings |  | $ 100,000,000.0
Minimum interest coverage ratio | 3.0 |
Maximum net leverage ratio | 3.5 |
Bottom of range [member] | Revolving Credit Facility [Member] |  |
Debt and Financing Obligations [Line Items] |  |
Line of credit facility, maximum borrowing capacity | $ 400,000,000.0 |
Commitment fee | 0.42% |
Top of range [member] | Revolving Credit Facility [Member] |  |
Debt and Financing Obligations [Line Items] |  |
Line of credit facility, maximum borrowing capacity | $ 500,000,000.0 |
LIBOR [Member] | Bottom of range [member] | Revolving Credit Facility - Drawn Amounts [Member] |  |
Debt and Financing Obligations [Line Items] |  |
Borrowings, adjustment to interest rate basis | 1.875% |

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- Definition [Line Items] for Debt and Financing Obligations [Table] + References No definition available. + Details
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- Definition Line Of Credit Facility Unused Capacity Commitment Fee Percentage1 + References No definition available. + Details
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- Definition Line of Credit Facility, Maximum Borrowing Capacity1 + References No definition available. + Details
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- Definition Maximum Net Leverage Ratio + References No definition available. + Details
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- Definition Minimum Interest Coverage Ratio + References No definition available. + Details
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- Definition The amount of outstanding funds that the entity is obligated to repay. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 55 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_55&doctype=Standard -URIDate 2020-01-01 + Details
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- Definition The adjustment to the basis (reference rate) used for calculation of the interest rate on borrowings. [Refer: Borrowings] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IFRS -Number 7 -IssueDate 2020-01-01 -Paragraph 7 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_7&doctype=Standard -URIDate 2020-01-01 + Details
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- Details
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- Details
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- Details
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- Details
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- Details
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