Stock-Based Compensation (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Stock Options
Outstanding at the beginning of period (in shares)	2,459,000
Granted (in shares)	233,000
Exercised (in shares)	0
Canceled/expired/forfeited (in shares)	(42,000)
Outstanding at the end of period (in shares)	2,650,000
Weighted Average Exercise Price
Outstanding weighted average exercise price at the beginning of period (in dollars per share)	$ 11.50	[1]
Granted (in dollars per share)	$ 3.36	[1]
Exercisted (in dollars per share)	$ 0.00	[1]
Canceled/expired/forfeited (in dollars per share)	$ 10.60	[1]
Outstanding weighted average exercise price at the end of period (in dollars per share)	$ 10.80	[1]
Stock Options
Share-based compensation disclosures
Award vesting period	3 years
Sare-based compensation, expiration date	5 years
Compensation expense	$ 0.2		$ 0.3
Performance Share Units
Share-based compensation disclosures
Award vesting period	3 years
Sare-based compensation, expiration date	3 years
Compensation expense	0.6		0.6
Stock units activity
Outstanding at the beginning of period (in shares)	845,000
Granted (in shares)	933,000
Canceled/expired/forfeited (in shares)	12,000
Outstanding at the end of period (in shares)	1,766,000
Weighted-Average Award Price
Outstanding at the beginning of period (in dollars per share)	$ 11.95
Granted (in dollars per share)	$ 4.21
Canceled/expired/forfeited (in dollars per share)	$ 12.01
Outstanding at the end of period (in dollars per share)	$ 7.86
Restricted Stock Units
Share-based compensation disclosures
Compensation expense	$ 0.6		$ 0.4
Stock units activity
Outstanding at the beginning of period (in shares)	534,000
Granted (in shares)	965,000
RSUs Vested and common shares issued (in shares)	(151,000)
Canceled/expired/forfeited (in shares)	22,000
Outstanding at the end of period (in shares)	1,326,000
Weighted-Average Award Price
Outstanding at the beginning of period (in dollars per share)	$ 9.30
Granted (in dollars per share)	$ 3.31
Vested and common shares issued (in dollars per share)	$ 8.82
Canceled/expired/forfeited (in dollars per share)	$ 8.82
Outstanding at the end of period (in dollars per share)	$ 5.00
Employee Stock Purchase Plan
Share-based compensation disclosures
Award vesting period	3 years
Maximum | Stock Options
Share-based compensation disclosures
Stock options exercisable, period	10 years

[1] The weighted-average exercise price of options outstanding is shown in US dollars as the majority of the options granted starting in 2011 have a strike price denominated in US dollars. Options with a Canadian dollar strike price have been converted to US dollars for disclosure purposes using the exchange rates on the respective date of grant.