Quarterly report pursuant to Section 13 or 15(d)

Treasury Stock and Share Based Awards - Additional Information (Detail)

v3.10.0.1
Treasury Stock and Share Based Awards - Additional Information (Detail)
$ / shares in Units, $ in Thousands
9 Months Ended
Sep. 30, 2018
USD ($)
$ / shares
shares
Restricted Stock  
Stockholders Equity Note [Line Items]  
Number of restricted shares 321,406
Market value of common stock on the dates of grant | $ / shares $ 38.79
Restricted Stock | Minimum  
Stockholders Equity Note [Line Items]  
Market value of common stock on the dates of grant | $ / shares $ 35.81
Forfeiture rate for restricted stock awards 0.00%
Award vesting period for restricted stock 1 year
Restricted Stock | Maximum  
Stockholders Equity Note [Line Items]  
Market value of common stock on the dates of grant | $ / shares $ 39.26
Forfeiture rate for restricted stock awards 10.00%
Award vesting period for restricted stock 4 years
Unvested Restricted Stock Awards  
Stockholders Equity Note [Line Items]  
Unrecognized compensation expense | $ $ 17,360
Remaining Compensation Expense recognition period (in years) 2 years
Restricted Stock Units (RSUs)  
Stockholders Equity Note [Line Items]  
Unrecognized compensation expense | $ $ 8,835
Remaining Compensation Expense recognition period (in years) 2 years
Number of hypothetical shares of common stock 228,194
Share-based compensation arrangement by share-based payment award, description The financial performance factors are based on an implied equity value concept that determines an internal rate of return (“IRR”) during the two fiscal year periods ending December 31, 2019 based on a formula utilizing a multiple of Adjusted EBITDA subject to certain adjustments as specified by the Compensation Committee prior to the grant date
Internal rate of return, performance period 2 years
Percentage of IRR, which is the threshold 7.00%
Percentage of IRR, which is the target 9.50%
Percentage of IRR, which is the maximum 13.00%
Percentage of IRR expected 11.00%
Share-based compensation arrangement by share-based payment award, vesting condition All restricted stock units granted during 2018 will vest subject to an additional two-year service requirement and will be paid in the form of common stock if the participant continues to provide services through the fourth anniversary of the grant date
Number of hypothetical shares of common stock at maximum IRR level 594,266
Actual cumulative forfeitures (in units) 18,667
Restricted Stock Units (RSUs) | Stock Grants 2016  
Stockholders Equity Note [Line Items]  
Percentage of IRR, which is the target 8.00%
Achieved Percentage of IRR 7.20%
Reduction in compensation expense | $ $ 69
Restricted Stock Units (RSUs) | Minimum  
Stockholders Equity Note [Line Items]  
Market value of common stock on the dates of grant | $ / shares $ 37.55
Expected forfeiture rate 0.00%
Restricted Stock Units (RSUs) | Maximum  
Stockholders Equity Note [Line Items]  
Market value of common stock on the dates of grant | $ / shares $ 39.03
Expected forfeiture rate 5.00%
Restricted Stock Units (RSUs) | Maximum | Threshold IRR  
Stockholders Equity Note [Line Items]  
Vesting percentage of restricted stock units 76,065
Restricted Stock Units (RSUs) | Maximum | Targeted IRR  
Stockholders Equity Note [Line Items]  
Vesting percentage of restricted stock units 152,129
Restricted Stock Units (RSUs) | Maximum | Maximum IRR  
Stockholders Equity Note [Line Items]  
Vesting percentage of restricted stock units 100.00%