Annual report pursuant to Section 13 and 15(d)

Capital Stock - Additional Information (Detail)

v3.20.4
Capital Stock - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Stockholders Equity Note [Line Items]      
Preferred stock, shares issued 0    
Preferred stock, shares outstanding 0    
Incremental stock-based compensation expense arising from the modification $ 521    
Restricted Stock      
Stockholders Equity Note [Line Items]      
Number of restricted shares granted 1,555,361 315,899 328,734
Market value of common stock on the dates of grant $ 17.68 $ 37.34 $ 38.72
Restricted stock grants vested 832,609 209,821 250,442
Unrecognized compensation expense $ 20,183    
Remaining Compensation Expense recognition period (in years) 2 years    
Restricted Stock | ASC Topic 718      
Stockholders Equity Note [Line Items]      
Restricted stock grants vested 191,983    
Restricted Stock | Directors      
Stockholders Equity Note [Line Items]      
Award vesting period for restricted stock 1 year    
Restricted Stock | Employees      
Stockholders Equity Note [Line Items]      
Restricted stock grants vested 300,891    
Restricted Stock | Minimum      
Stockholders Equity Note [Line Items]      
Market value of common stock on the dates of grant $ 8.39    
Forfeiture rate for restricted stock awards 0.00%    
Restricted Stock | Minimum | Employees      
Stockholders Equity Note [Line Items]      
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 $ 32.12    
Forfeiture rate for restricted stock awards 10.00%    
Restricted Stock | Maximum | Employees      
Stockholders Equity Note [Line Items]      
Award vesting period for restricted stock 4 years    
Restricted Stock Units (RSUs)      
Stockholders Equity Note [Line Items]      
Market value of common stock on the dates of grant $ 32.12 $ 36.77  
Restricted stock grants vested 208,204 90,895 127,084
Unrecognized compensation expense     $ 11,849
Remaining Compensation Expense recognition period (in years) 2 years    
Number of hypothetical shares of common stock 436,681 306,651 228,194
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”) 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%    
Percentage of IRR, which is the threshold, before modification   7.00%  
Percentage of IRR, which is the target before modification   9.50%  
Percentage of IRR, which is the maximum before modification   13.00%  
Percentage of IRR, which is the threshold 6.00% 6.00% 6.00%
Percentage of IRR, which is the target 8.00% 8.00% 8.00%
Percentage of IRR, which is the maximum 14.00% 14.00% 14.00%
Number of hypothetical shares of common stock at maximum IRR level 890,680    
Restricted Stock Units (RSUs) | Stock Grants 2016      
Stockholders Equity Note [Line Items]      
Impact of modification of awards   $ 132  
Achieved Percentage of IRR 9.30%    
Impact of final performance measure   $ 563  
Restricted Stock Units (RSUs) | Stock Grant 2017      
Stockholders Equity Note [Line Items]      
Achieved Percentage of IRR   9.30%  
Restricted Stock Units (RSUs) | Stock Grant 2018      
Stockholders Equity Note [Line Items]      
Achieved Percentage of IRR 8.00%    
Restricted Stock Units (RSUs) | ASC Topic 718      
Stockholders Equity Note [Line Items]      
Restricted stock grants vested 87,911    
Weighted average grant date fair value per share as of date of modification $ 15.95    
Incremental stock-based compensation expense arising from the modification $ 521    
Restricted Stock Units (RSUs) | Minimum      
Stockholders Equity Note [Line Items]      
Market value of common stock on the dates of grant     $ 37.55
Expected forfeiture rate 0.00% 0.00% 0.00%
Restricted Stock Units (RSUs) | Maximum      
Stockholders Equity Note [Line Items]      
Market value of common stock on the dates of grant     $ 39.03
Expected forfeiture rate 5.00% 5.00% 5.00%