Share-Based Compensation Plans (Option Assumptions Used in Black-Scholes) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Plans Option Assumptions Used In Black-scholes Details
Dividend yield	$ 0	$ 0	$ 0
Expected volatility, minimum	57.98%	59.15%	61.22%
Expected volatility, maximum	60.69%	60.69%	67.58%
Risk-free interest rate, minimum	1.40%	0.70%	0.60%
Risk-free interest rate, maximum	1.80%	3.70%	1.10%
Expected term, in years, minimum	5 years 73 days	5 years 73 days	5 years 37 days
Expected term, in years, maximum	5 years 219 days	6 years	5 years 329 days