Compensation Plans (Schedule of FV Assumptions) (Details)	12 Months Ended
Dec. 31, 2017 $ / shares	Dec. 31, 2016 $ / shares	Dec. 31, 2015 $ / shares	Dec. 31, 2017 CAD / shares	Dec. 31, 2016 CAD / shares	Dec. 31, 2015 CAD / shares
United States Of America Dollars [Member]
Fair Value Assumptions, Risk Free Interest Rate	1.67%	0.75%	0.48%
Fair Value Assumption Dividend Yield	0.45%	0.51%	1.18%
Fair Value Assumptions, Expected Volatility Rate	57.87%	57.18%	39.16%
Fair Value Assumptions, Expected Term	1 year 4 months 24 days	1 year 10 months 24 days	1 year 4 months 24 days
Market Share price \| $ / shares	$ 13.33	$ 11.74	$ 5.09
Canadian Dollar [Member]
Fair Value Assumptions, Risk Free Interest Rate	1.67%	0.75%	0.48%
Fair Value Assumption Dividend Yield	0.46%	0.50%	1.09%
Fair Value Assumptions, Expected Volatility Rate	54.10%	53.24%	36.45%
Fair Value Assumptions, Expected Term	1 year 6 months	1 year 10 months 24 days	1 year 6 months
Market Share price \| CAD / shares				CAD 16.77	CAD 15.76	CAD 7.03

Expected dividends to be paid to holders of the underlying shares or financial instruments (expressed as a percentage of the share or instrument's price).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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Period the instrument, asset or liability is expected to be outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Risk-free interest rate assumption used in valuing an instrument.

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Weighted average expected volatility of stock price.

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- Definition

Price of a single share of a number of saleable stocks of a company.

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