XML 102 R88.htm IDEA: XBRL DOCUMENT v3.8.0.1
Stock-Based Compensation, Stock Option Activity (Details) - USD ($)
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Fair value assumptions of stock options      
Dividend yield 2.00% 2.50% 2.00%
Risk-free interest rate 2.00% 2.00% 2.00%
Weighted average expected volatility 25.00% 25.00% 20.00%
Weighted average expected life 5 years 6 months 5 years 6 months 6 years
Weighted average per share fair value of stock options (in usd per share) $ 5.30 $ 3.36 $ 3.08
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]      
Stock Options Shares Outstanding, Beginning balance (in shares) 6,357,843    
Granted (in shares) 799,558    
Exercised (in shares) (1,551,669)    
Forfeited or expired (in shares) (487,045)    
Stock Options Shares Outstanding, Ending balance (in shares) 5,118,687 6,357,843  
Options exercisable (in shares) 2,831,736    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]      
Stock Options Outstanding, Weighted Average Exercise Price, Beginning balance (in usd per share) $ 17.67    
Granted, Weighted Average Exercise Price (in usd per share) 25.61    
Exercised, Weighted Average Exercise Price (in usd per share) 16.87    
Forfeited or expired, Weighted Average Exercise Price (in usd per share) 31.84    
Stock Options Outstanding, Weighted Average Exercise Price, Ending balance (in usd per share) 18.02 $ 17.67  
Options Exercisable, Weighted Average Exercise Price (in usd per share) $ 16.31    
Stock Options Outstanding, Weighted Average Remaining Contractual Term 6 years 5 months 23 days 6 years 1 month 6 days  
Options exercisable, Weighted Average Remaining Contractual Term 5 years 2 months 23 days    
Stock Options Outstanding, Aggregate Intrinsic Value $ 38,028 $ 47,902  
Options exercisable, Aggregate Intrinsic Value $ 25,738