XML 104 R74.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Share-Based Compensation , Narrative (Details) - USD ($)
$ / shares in Units, $ in Millions
3 Months Ended 12 Months Ended
Mar. 31, 2019
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Employee Service Share-based Compensation, Nonvested Awards, Expected Compensation Cost To Be Recognized In Next Twelve Months $ 16.6      
Share-based Compensation Expense   $ 17.5 $ 15.1 $ 12.7
Vested in Period, Total Fair Value   15.3 $ 11.7 $ 9.3
Compensation Cost Not yet Recognized   $ 39.0    
Employee Service Share-based Compensation, Nonvested Awards, Expected Compensation Cost To Be Recognized In Two Years 11.3      
Employee Service Share-based Compensation, Nonvested Awards, Expected Compensation Cost To Be Recognized In Three Years 7.1      
Employee Service Share-based Compensation, Nonvested Awards, Expected Compensation Cost To Be Recognized After Three Years $ 4.0      
Two Thousand Fifteen Equity Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Number of Shares Available for Grant   974,864    
Number of Shares Authorized 1,750,000      
Director Plans [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Number of Shares Available for Grant   191,774    
Number of Shares Authorized   375,000    
2004 Non-employee Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized 200,000      
Restricted Stock [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Granted shares   190,020 233,400 219,400
Weighted Average Grant Date Fair Value $ 87.12 $ 117.47   $ 79.38
Restricted Stock [Member] | Two Thousand Fifteen Equity Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Granted shares     16,500  
Weighted Average Grant Date Fair Value     $ 88.30  
2004 Non-employee Plan [Member] | Share-based Payment Arrangement [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Outstanding options   1,500    
Executive Officer [Member] | Time Based [Member] | Two Thousand Fifteen Equity Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Award Vesting Rights, Percentage   20.00% 20.00%  
Award Vesting Period   5 years 5 years  
Executive Officer [Member] | Restricted Stock [Member] | Two Thousand Fifteen Equity Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Award Vesting Rights, Percentage   100.00% 100.00%  
Key Employees [Member] | Time Based [Member] | Two Thousand Fifteen Equity Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Award Vesting Rights, Percentage   20.00% 20.00%  
Award Vesting Period   5 years 5 years  
Director [Member] | Restricted Stock [Member] | 2004 Non-employee Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Granted shares   18,000 16,800  
Weighted Average Grant Date Fair Value   $ 113.68 $ 85.28  
Award Vesting Rights, Percentage   100.00% 100.00%  
Share-based Payment Arrangement, Tranche Two [Member] | Restricted Stock [Member] | Two Thousand Fifteen Equity Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Granted shares     50,100  
Weighted Average Grant Date Fair Value     $ 86.97  
Award Vesting Rights, Percentage     35.00%  
Share-based Payment Arrangement, Tranche Three [Member] | Restricted Stock [Member] | Two Thousand Fifteen Equity Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Award Vesting Rights, Percentage     20.00%  
Share-based Compensation Award, Tranche Four [Member] | Restricted Stock [Member] | Two Thousand Fifteen Equity Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Award Vesting Rights, Percentage     5.00%  
Share-based Compensation Award, Tranche Five [Member] | Restricted Stock [Member] | Two Thousand Fifteen Equity Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Award Vesting Rights, Percentage     5.00%  
Share-based Payment Arrangement, Tranche One [Member] | Restricted Stock [Member] | Two Thousand Fifteen Equity Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Award Vesting Rights, Percentage     35.00%