Quarterly report pursuant to Section 13 or 15(d)

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

v3.8.0.1
Treasury Stock and Share Based Awards - Additional Information (Detail)
$ / shares in Units, $ in Thousands
3 Months Ended
Mar. 31, 2018
USD ($)
$ / shares
shares
Restricted Stock  
Stockholders Equity Note [Line Items]  
Number of restricted shares 260,019
Market value of common stock on the dates of grant | $ / shares $ 39.03
Restricted Stock | Tranche One  
Stockholders Equity Note [Line Items]  
Award vesting period for restricted stock 2 years
Restricted Stock | Tranche Two  
Stockholders Equity Note [Line Items]  
Award vesting period for restricted stock 4 years
Restricted Stock | Minimum  
Stockholders Equity Note [Line Items]  
Forfeiture rate for restricted stock awards 0.00%
Restricted Stock | Maximum  
Stockholders Equity Note [Line Items]  
Forfeiture rate for restricted stock awards 10.00%
Unvested Restricted Stock Awards  
Stockholders Equity Note [Line Items]  
Unrecognized compensation expense | $ $ 20,005
Remaining Compensation Expense recognition period (in years) 2 years
Restricted Stock Units (RSUs)  
Stockholders Equity Note [Line Items]  
Market value of common stock on the dates of grant | $ / shares $ 39.03
Unrecognized compensation expense | $ $ 10,776
Remaining Compensation Expense recognition period (in years) 2 years
Number of hypothetical shares of common stock 224,602
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 February 2022, which is the fourth anniversary of the grant date
Expected forfeiture rate 5.00%
Number of hypothetical shares of common stock at maximum IRR level 596,726
Actual cumulative forfeitures (in units) 13,690
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) | Maximum | Threshold IRR  
Stockholders Equity Note [Line Items]  
Vesting percentage of restricted stock units 74,867
Restricted Stock Units (RSUs) | Maximum | Targeted IRR  
Stockholders Equity Note [Line Items]  
Vesting percentage of restricted stock units 149,735
Restricted Stock Units (RSUs) | Maximum | Maximum IRR  
Stockholders Equity Note [Line Items]  
Vesting percentage of restricted stock units 100.00%