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Financing Obligations (Revolving Credit Facility) (Details) |  | 12 Months Ended |
--- | --- | --- | ---
Sep. 21, 2017 USD ($) | Dec. 31, 2017 USD ($) | Sep. 20, 2017 USD ($)
Revolving Credit Facility [Member] |  |  |
Debt and Financing Obligations [Line Items] |  |  |
Line of credit facility, maximum borrowing capacity | $ 400,000,000.0 |  | $ 150,000,000.0
Minimum interest coverage ratio | 3.0 |  |
Maximum net leverage ratio | 3.5 |  |
Borrowing costs incurred |  | $ 2,100,000 |
Bottom of range [member] | Revolving Credit Facility [Member] |  |  |
Debt and Financing Obligations [Line Items] |  |  |
Commitment fee | 0.45% |  |
Top of range [member] | Revolving Credit Facility [Member] |  |  |
Debt and Financing Obligations [Line Items] |  |  |
Commitment fee | 0.70% |  |
LIBOR [Member] | Bottom of range [member] | Revolving Credit Facility - Drawn Amounts [Member] |  |  |
Debt and Financing Obligations [Line Items] |  |  |
Borrowings, adjustment to interest rate basis | 2.00% |  |
LIBOR [Member] | Top of range [member] | Revolving Credit Facility - Drawn Amounts [Member] |  |  |
Debt and Financing Obligations [Line Items] |  |  |
Borrowings, adjustment to interest rate basis | 3.125% |  |

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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 interest and other costs that an entity incurs in connection with the borrowing of funds. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2017-01-01 -Paragraph 112 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_112_c&doctype=Standard -URIDate 2017-03-09 + 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 2017-01-01 -Paragraph 7 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2017-03-01&anchor=para_7&doctype=Standard -URIDate 2017-03-09 + Details
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- Details
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- Details
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