Stock Option Plans - Summary of Stock Option Outstanding and Exercisable (Details)	12 Months Ended
	Dec. 31, 2014 USD ($)	Dec. 31, 2014 CAD	Dec. 31, 2013 USD ($)	Dec. 31, 2013 CAD	Dec. 31, 2012 USD ($)	Dec. 31, 2012 CAD	Dec. 31, 2011 USD ($)	Dec. 31, 2011 CAD	Dec. 31, 2014 CAD $2.67 USD ($)	Dec. 31, 2014 CAD $2.67 CAD	Dec. 31, 2014 CAD $3.74 USD ($)	Dec. 31, 2014 CAD $3.74 CAD	Dec. 31, 2014 CAD$ 6.07 USD ($)	Dec. 31, 2014 CAD$ 6.07 CAD	Dec. 31, 2014 CAD$ 9.76 USD ($)	Dec. 31, 2014 CAD$ 9.76 CAD	Dec. 31, 2014 CAD$ 10.78 USD ($)	Dec. 31, 2014 CAD$ 10.78 CAD	Dec. 31, 2014 CAD$ 11.22 USD ($)	Dec. 31, 2014 CAD$ 11.22 CAD	Dec. 31, 2014 USD$ 9.00 USD ($)	Dec. 31, 2014 USD$ 9.00 CAD	Dec. 31, 2014 USD$ 12.65 USD ($)	Dec. 31, 2014 USD$ 12.65 CAD
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options Outstanding, Weighted Average Exercise Price	$ 4.20	4.88	$ 3.88	3.98	$ 4.17	4.13	$ 4.22	4.27	$ 2.30	2.67	$ 3.22	3.74	$ 5.23	6.07	$ 8.41	9.76	$ 9.29	10.78	$ 9.67	11.22	$ 9.00	10.44	$ 12.65	14.68
Options exercisable, Weighted Average Exercise Price	$ 3.44	3.99							$ 2.30	2.67	$ 3.22	3.74	$ 5.23	6.07	$ 8.41	9.76	$ 9.29	10.78		11.22	$ 9.00		$ 12.65	14.68
Number of Options Outstanding	1,484,218	1,484,218	1,333,099	1,333,099	1,128,437	1,128,437	1,059,510	1,059,510	252,353	252,353	878,149	878,149	107,013	107,013	42,592	42,592	156,172	156,172	6,273	6,273	36,008	36,008	5,658	5,658
Options Outstanding Weighted Average Remaining Option Life in Years	5 years 8 months 12 days	5 years 8 months 12 days	5 years 9 months 18 days	5 years 9 months 18 days	5 years 9 months 22 days	5 years 9 months 22 days	6 years 26 days	6 years 26 days	8 years 15 days	8 years 15 days	4 years 8 months 27 days	4 years 8 months 27 days	2 months 9 days	2 months 9 days	8 years 7 months 2 days	8 years 7 months 2 days	9 years 15 days	9 years 15 days	9 years 7 months 2 days	9 years 7 months 2 days	9 years 10 months 6 days	9 years 10 months 6 days	9 years 10 months 24 days	9 years 10 months 24 days
Number of Options Exercisable	1,116,564	1,116,564							133,053	133,053	851,569	851,569	107,013	107,013	15,085	15,085	7,525	7,525					2,319	2,319