Stock Based Compensation Share-based Compensation - Summary of Weighted Average Valuation Assumptions for Market Condition Performance Restricted Stock Units (Details) - Market Condition Based PRSUs	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	0.00%	0.00%	0.00%
Expected life (in years)	2 years 10 months 6 days	2 years 10 months 2 days	2 years 10 months 17 days
Risk free interest rate (as a percent)	0.88%	0.98%	0.65%
Volatility (as a percent)	28.00%	30.30%	30.40%