XML 51 R40.htm IDEA: XBRL DOCUMENT v3.5.0.2
Stock-based Compensation - Additional Information (Detail) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
May 16, 2016
Jun. 30, 2016
Jun. 30, 2015
Jun. 30, 2016
Jun. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Additional shares of common stock authorized, available for issuance (in shares) 600,000        
Shares of common stock reserved for issuance (in shares)   2,400,000   2,400,000  
Shares of common stock available for issuance (in shares)   767,213   767,213  
Restricted Stock Units (RSUs) [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Share settlement under RSUs (in shares)       17,333 35,486
Cash used for employee withholding tax payments       $ 1.3 $ 4.8
Unamortized stock-based compensation expense   $ 17.6   $ 17.6  
Weighted-average remaining amortization period       1 year 9 months 18 days  
Stock Options [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Contractual life       10 years  
Vesting period       3 years  
Stock-based compensation expense   $ 3.4 $ 3.4 $ 6.7 $ 6.4
Restricted Stock Units (RSUs), Performance-Based [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Company granted performance contingent RSU (in shares)       33,244  
Measurement period for growth in operating income       1 year  
Measurement period for total shareholder return       3 years  
Stock-based compensation expense       $ 0.1  
Minimum [Member] | Restricted Stock Units (RSUs) [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Contractual life       1 year  
Maximum [Member] | Restricted Stock Units (RSUs) [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Contractual life       3 years