XML 121 R101.htm IDEA: XBRL DOCUMENT v3.8.0.1
Long-term Incentive Compensation and Shareholders Equity - Summary of Weighted Average Valuation Inputs (Details) - Stock Options and Stock Appreciation Rights
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected term 4 years 2 months 12 days 4 years 2 months 12 days 4 years 1 month 6 days
Expected volatility 23.90% 21.00% 24.60%
Expected dividend yield 0.00% 0.00% 0.00%
Risk-free interest rate 1.70% 1.00% 1.50%