Stock Based Compensation - Summary of Option Activity (Details) (Stock Options) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Third Amended and Restated 1997 Stock Option Plan USD ($)	Dec. 31, 2012 Third Amended and Restated 1997 Stock Option Plan CAD	Dec. 31, 2011 Third Amended and Restated 1997 Stock Option Plan USD ($)	Dec. 31, 2011 Third Amended and Restated 1997 Stock Option Plan CAD	Dec. 31, 2010 Third Amended and Restated 1997 Stock Option Plan USD ($)	Dec. 31, 2010 Third Amended and Restated 1997 Stock Option Plan CAD
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding as of beginning of year (options)				8,539	8,539	6,724	6,724	7,283	7,283
Options granted (options)	5,164	2,288	1,599	5,164	5,164	2,288	2,288	1,599	1,599
Options exercised (options)				(203)	(203)	(159)	(159)	(1,149)	(1,149)
Options forfeited, canceled and expired (options)				(1,163)	(1,163)	(314)	(314)	(1,009)	(1,009)
Options outstanding as of end of year (options)				12,337	12,337	8,539	8,539	6,724	6,724
Options exercisable as of year end				7,920	7,920	6,233	6,233	4,622	4,622
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Options outstanding as of beginning of year - Weighted average exercise price					3.18		3.35		3.19
Options granted - Weighted average exercise price					1.94		2.67		3.77
Options exercised - Weighted average exercise price					1.45		1.78		2.11
Options forfeited, canceled and expired - Weighted average exercise price					2.74		3.67		4.27
Options outstanding as of end of year - Weighted average exercise price					2.74		3.18		3.35
Options exercisable as of March 30, 2012 - Weighted average exercise price exercisable					3.04		3.30		3.48
Share Based Compensation Arrangement By Share Based Payment Award, Options Outstanding, Weighted Average Remaining Contractual Term, Rollforward [Roll Forward]
Options outstanding as of beginning of year - Weighted average remaining contractual term				6 years 2 months 12 days	6 years 2 months 12 days	7 years	7 years	7 years	7 years
Options granted - Weighted average remaining contractual term				6 years 4 months 24 days	6 years 4 months 24 days	9 years 3 months 18 days	9 years 3 months 18 days	9 years 3 months 18 days	9 years 3 months 18 days
Options exercised - Weighted average remaining contractual term				3 years 6 months	3 years 6 months	4 years 7 months 6 days	4 years 7 months 6 days	5 years 4 months 24 days	5 years 4 months 24 days
Options forfeited, canceled and expired - Weighted average remaining contractual term				6 years	6 years	6 years 9 months 18 days	6 years 9 months 18 days	0 years	0 years
Options outstanding as of end of year - Weighted average remaining contractual term				6 years 2 months 12 days	6 years 2 months 12 days	7 years	7 years	7 years	7 years
Options exercisable as of end of year - Weighted average remaining contractual term				5 years 8 months 12 days	5 years 8 months 12 days	6 years 2 months 12 days	6 years 2 months 12 days	6 years 3 months 18 days	6 years 3 months 18 days
Share Based Compensation Arrangement By Share Based Payment Award, Options Outstanding, Weighted Average RemainingTerm, Rollforward [Roll Forward]
Options outstanding as of beginning of year - Aggregate intrinsic value					95		9,001		4,221
Options granted in period - Aggregate intrinsic value					0		0		0
Options exercised - Aggregate intrinsic value				100	125	300	0	2,400	2,423
Options forfeited, canceled and expired - Aggegrate intrinsic value					0		0		0
Options outstanding as of end of year - Aggregate intrinsic value					541		95		9,001
Options exercisable as of end of year - Aggregate intrinsic value					356		95		5,770