Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2011

Significant Accounting Policies

Weighted average assumptions for the Black-Scholes method used to estimate fair value of stock option grants

	2011	2010	2009
Range of expected lives of options (years)	4.75	4.75	4.75
Range of expected stock price volatilities	53.0% - 56.6%	52.4% - 53.9%	42.0% - 52.0%
Weighted average expected stock price volatilities	53.2%	53.3%	46.3%
Range of risk-free interest rates	0.8% - 2.1%	1.2% - 2.5%	1.3% - 2.1%
Expected dividend yield	0.0%	0.0%	0.0%