Annual report pursuant to Section 13 and 15(d)

Capital Stock - Additional Information (Detail)

v3.10.0.1
Capital Stock - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Stockholders Equity Note [Line Items]      
Preferred stock, shares issued 0    
Preferred stock, shares outstanding 0    
Restricted Stock      
Stockholders Equity Note [Line Items]      
Number of hypothetical shares of common stock 328,734    
Market value of common stock on the dates of grant $ 38.72 $ 41.70 $ 30.98
Unrecognized compensation expense $ 15,174    
Remaining Compensation Expense recognition period (in years) 2 years    
Restricted Stock | Directors      
Stockholders Equity Note [Line Items]      
Award vesting period for restricted stock granted 1 year    
Restricted Stock | Minimum      
Stockholders Equity Note [Line Items]      
Market value of common stock on the dates of grant $ 35.80    
Forfeiture rate for restricted stock awards 0.00%    
Restricted Stock | Minimum | Employees      
Stockholders Equity Note [Line Items]      
Award vesting period for restricted stock granted 1 year    
Restricted Stock | Maximum      
Stockholders Equity Note [Line Items]      
Market value of common stock on the dates of grant $ 39.26    
Forfeiture rate for restricted stock awards 10.00%    
Restricted Stock | Maximum | Employees      
Stockholders Equity Note [Line Items]      
Award vesting period for restricted stock granted 4 years    
Restricted Stock Units (RSUs)      
Stockholders Equity Note [Line Items]      
Number of hypothetical shares of common stock 228,194 175,634 253,661
Market value of common stock on the dates of grant   $ 42.37 $ 29.83
Unrecognized compensation expense $ 8,416    
Remaining Compensation Expense recognition period (in years) 2 years    
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”) for a two year measurement period, as defined in the award agreement, based on a formula utilizing a multiple of Adjusted EBITDA subject to certain specified adjustments (as defined in the restricted stock unit award agreement).  
Share-based compensation arrangement by share-based payment award, vesting condition   All payouts of restricted stock units that vest will be subject to an additional 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.  
Internal rate of return, performance period 2 years    
Percentage of IRR expected 9.00%    
Expected forfeiture rate 5.00%    
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 2015      
Stockholders Equity Note [Line Items]      
Stock price at the date of modification     $ 37.98
Incremental compensation expense     $ 562
Restricted Stock Units (RSUs) | Stock Grant 2016      
Stockholders Equity Note [Line Items]      
Actual IRR calculated for grant 7.20%    
Restricted Stock Units (RSUs) | Stock Grant 2017      
Stockholders Equity Note [Line Items]      
Actual IRR calculated for grant 11.20%    
Restricted Stock Units (RSUs) | Stock Grant 2018      
Stockholders Equity Note [Line Items]      
Actual IRR calculated for grant 9.50%    
Restricted Stock Units (RSUs) | Minimum      
Stockholders Equity Note [Line Items]      
Market value of common stock on the dates of grant $ 39.03    
Restricted Stock Units (RSUs) | Maximum      
Stockholders Equity Note [Line Items]      
Market value of common stock on the dates of grant $ 37.55