ShareBased Compensation Performance-Based Valuation Assumptions Table (Details) (PBRSU [Member])	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013
PBRSU [Member]
Schedule of Share-based Payment Awards, Performance-Based, Valuation Assumptions [Line Items]
Expected dividend yield	0.00%		0.00%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate	0.74%	[1]	0.41%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate	27.88%	[2]	29.87%
Share-based Compensation Arrangement, Fair Value, Average Shareholder Return	(0.90%)	[2]	17.87%

[1] The risk-free interest rate for the periods within the contractual term of the PBRSUs is based on the U.S. Treasury yield curve in effect at the time of the grant.

[2] The expected volatility and average total shareholder return is a measure of the amount by which a stock price has fluctuated or is expected to fluctuate based primarily on our and our peers' historical data.