XML 52 R42.htm IDEA: XBRL DOCUMENT v3.7.0.1
Stock-Based Compensation - Assumptions (Details) - Stock options
6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Stock-Based Compensation    
Risk-free interest rates, minimum (as a percent) 1.78% 1.27%
Risk-free interest rates, maximum (as a percent) 2.09% 2.05%
Expected life 5 years 6 months 22 days  
Volatility, minimum (as a percent) 31.41% 33.75%
Volatility, maximum (as a percent) 34.13% 41.60%
Minimum    
Stock-Based Compensation    
Vesting period 3 years  
Expected life   5 years 9 months
Expected dividend yield (as a percent) 0.58% 0.00%
Maximum    
Stock-Based Compensation    
Vesting period 4 years  
Expected life   7 years 7 days
Expected dividend yield (as a percent) 0.74% 0.66%