Share-Based Compensation Plans (Details) (USD $)	12 Months Ended
	Dec. 31, 2012
SAR's 2010 [Member]
Assumptions to estimate fair value of stock options and SAR's
Weighted average fair value of stock options granted and SAR's outstanding	$ 13.73
Expected volatility	51.57%
Expected life	2 years 8 months 12 days
Risk-free interest rate	0.34%
Expected dividend yield	0.00%
Date of Grant [Member] | Stock Options 2012 [Member]
Assumptions to estimate fair value of stock options and SAR's
Weighted average fair value of stock options granted and SAR's outstanding	$ 15.77
Expected volatility	70.56%
Expected life	5 years 6 months
Risk-free interest rate	0.89%
Expected dividend yield	0.00%
Date of Grant [Member] | Stock Options 2011 [Member]
Assumptions to estimate fair value of stock options and SAR's
Weighted average fair value of stock options granted and SAR's outstanding	$ 17.85
Expected volatility	72.56%
Expected life	6 years
Risk-free interest rate	2.30%
Expected dividend yield	0.00%