Annual report pursuant to Section 13 and 15(d)

STOCK-BASED COMPENSATION - Narrative (Details)

v3.19.3.a.u2
STOCK-BASED COMPENSATION - Narrative (Details)
$ in Millions
1 Months Ended 12 Months Ended
May 31, 2013
shares
Dec. 31, 2019
USD ($)
plan
shares
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Number of share-based award plans | plan   1    
Increase in reserve under share-based award plan, number of shares (in shares) | shares 11,000,000      
Total income tax benefit recognized for stock-based compensation expense   $ 12.2 $ 9.7 $ 13.7
Stock options vesting percentage for each year of completed service   33.00%    
Stock options expiration periods   10 years    
Minimum percentage of target to which shares may be issued   0.00%    
Maximum percentage of target to which shares may be issued   200.00%    
Percentage of target that shares may be issued   100.00%    
Minimum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Share-based payment award options nonvested number of shares | shares   313,296    
Maximum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Share-based payment award options nonvested number of shares | shares   626,592    
Stock Options        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Total intrinsic value of stock options exercised   $ 18.6 13.3 31.4
Total unrecognized compensation cost   $ 8.4    
Total unrecognized compensation cost, weighted-average period of recognition   1 year 9 months 18 days    
Stock Options | Maximum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock awards vesting periods (up to)   3 years    
Nonvested Stock        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Total unrecognized compensation cost   $ 46.6    
Total unrecognized compensation cost, weighted-average period of recognition   1 year 9 months 18 days    
Total weighted-average fair value of nonvested stock vested, based on the vesting date   $ 32.6 50.2 79.4
Total weighted-average fair value of nonvested stock vested, based on the grant date   $ 30.5 $ 40.4 $ 45.0
Nonvested Stock | Minimum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock awards vesting periods (up to)   1 year    
Nonvested Stock | Maximum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock awards vesting periods (up to)   3 years