Financial Instruments and Risk Management - Interest Rate Risk (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Interest rate risk
Disclosure of nature and extent of risks arising from financial instruments [line items]
Reasonably possible change in risk variable, percentage	1.00%
Reasonably possible change in risk variable, impact on interest expense	$ 1.9
Credit Facility
Disclosure of nature and extent of risks arising from financial instruments [line items]
Borrowings	$ 187.5	$ 227.5

Sensitivity Analysis For Types Of Market Risk, Reasonably Possible Change In Risk Variable, Impact On Interest Expense

No definition available.

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- Definition

Sensitivity Analysis For Types Of Market Risk, Reasonably Possible Change In Risk Variable, Percent

+ 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 2017-01-01
-Paragraph 55
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_55&doctype=Standard
-URIDate 2017-03-09

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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.

+ Details

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