XML 69 R55.htm IDEA: XBRL DOCUMENT v3.10.0.1
Stock Incentive Plans - Additional Information (Detail)
 12 Months Ended
Dec. 31, 2018
USD ($)
Installment
$ / shares
shares
Dec. 31, 2017
USD ($)
shares
Dec. 31, 2016
USD ($)
$ / shares
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
New grants of stock option | shares 0    
Outstanding options expiration period from the date of grant 10 years    
Share-based compensation expense included in selling, general and administrative expenses $ 5,500,000 $ 4,200,000 $ 2,800,000
Share-based compensation, income tax benefits $ 1,500,000 $ 1,500,000 $ 1,100,000
Stock Options [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of equal annual installments options are exercisable | Installment 4    
Options exercisable period after date of grant 1 year    
Weighted average fair value of stock options, granted | $ / shares $ 36.41   $ 17.10
Stock options granted with an exercise price below market price | shares 0 0 0
Intrinsic value of stock options exercised $ 2,500,000 $ 479,000 $ 113,000
Fair value of shares vested during the period 312,000 328,000 319,000
Unrecognized compensation expense $ 4,300,000    
Weighted average remaining amortization period 7 years 1 month 6 days    
Restricted Stock Units [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Options exercisable period after date of grant 1 year    
Fair value of shares vested during the period $ 4,000,000 $ 3,300,000 $ 1,900,000
Unrecognized compensation expense $ 10,100,000    
Weighted average remaining amortization period 2 years 7 months 6 days    
Number of equal annual installments in which restricted stock units generally vest | Installment 4    
Performance Share Units (“PSUs”) [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting period 3 years    
Maximum payout percentage 200.00%    
Two Thousand And Fifteen Stock Incentive Plan [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of shares of common stock reserved for issuance under the 2015 Plan | shares 1,000,000    
Aggregate number of shares for which incentive stock options may be granted under the Plan | shares 900,000    
2009 Plan [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of shares available for grant | shares 506,295