XML 44 R52.htm IDEA: XBRL DOCUMENT v3.19.3
Stock-Based Compensation Plans - Additional Information (Details) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Sep. 30, 2019
Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock-based compensation expense $ 9,371 $ 6,575 $ 30,328 $ 20,642
Stock Options        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Incentive plan, weighted average grant date fair value of stock options granted (in dollars per share)       $ 7.03
Incentive plan, total intrinsic value of stock options exercised     6,900 $ 13,600
Unrecognized compensation costs 500   $ 500  
Unrecognized compensation costs, weighted average recognition period     6 months  
LTIP Performance Shares        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock-based compensation expense, additional expense due to changes in expected attainment rates     $ 6,000  
Unrecognized compensation costs 2,400   $ 2,400  
Unrecognized compensation costs, weighted average recognition period     6 months  
Restricted Share Awards (RSAs)        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Number of shares vested     106,610  
Shares withheld to pay employees' portion of minimum payroll withholding taxes     32,371  
Unrecognized compensation costs 800   $ 800  
Unrecognized compensation costs, weighted average recognition period     4 months 24 days  
Total Shareholder Return Awards (TSRs)        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Unrecognized compensation costs 23,200   $ 23,200  
Unrecognized compensation costs, weighted average recognition period     1 year 10 months 24 days  
Restricted Share Units (RSUs)        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Number of shares vested     259,634  
Shares withheld to pay employees' portion of minimum payroll withholding taxes     57,802  
Unrecognized compensation costs 23,900   $ 23,900  
Unrecognized compensation costs, weighted average recognition period     1 year 7 months 6 days  
2017 Employee Stock Purchase Plan        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Shares issued under ESPP     92,765 112,549
2016 Equity and Performance Incentive Plan        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock-based compensation expense 9,300 6,500 $ 30,300 $ 20,600
Stock-based compensation expense, tax benefits $ 1,500 $ 1,500 $ 5,500 $ 3,600