Quarterly report pursuant to Section 13 or 15(d)

Equity-Based Compensation - Additional Information (Detail)

v3.19.3
Equity-Based Compensation - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Thousands
1 Months Ended 3 Months Ended 9 Months Ended 12 Months Ended
May 31, 2019
Oct. 31, 2018
May 31, 2016
Aug. 31, 2015
Sep. 30, 2019
Sep. 30, 2018
Sep. 30, 2019
Sep. 30, 2018
Dec. 31, 2018
Nov. 02, 2012
Non-Qualified Stock Options                    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                    
Restricted stock units granted 60,742 105,398                
Restricted stock units\non-qualified stock options, granted description             One third of the NQOs will vest and become exercisable on each of the first, second and third anniversaries of the grant date.      
Fair value assumptions, strike price $ 14.54 $ 13.97                
Fair value assumptions, risk free rate 2.32% 2.94%                
Fair value assumptions, expiration 5 years 5 years                
Fair value assumptions, volatility 34.20% 32.70%                
Compensation expense forfeiture rate 1.00% 1.00%                
Compensation expense         $ 445 $ 832 $ 2,166 $ 2,433    
Unrecognized compensation expense related to unvested awards         1,051   $ 1,051   $ 2,392  
Recognition period of unrecognized compensation expense related to unvested awards             1 year 10 months 13 days   1 year 6 months 3 days  
Restricted Stock Units                    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                    
Restricted stock units granted             34,388      
Compensation expense         445 $ 832 $ 2,166 $ 2,433    
Unrecognized compensation expense related to unvested awards         $ 1,051   $ 1,051   $ 2,392  
Recognition period of unrecognized compensation expense related to unvested awards             1 year 10 months 13 days   1 year 6 months 3 days  
2012 Equity Incentive Plan                    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                    
Shares reserved for issuance         489,549   489,549      
Shares reserved for issuance, authorized                   1,687,500
Restricted stock units granted     3,791 966,510            
Fair Value per unit     $ 13.19 $ 13.23            
Restricted stock units\non-qualified stock options, granted description             Twenty-five percent of the RSUs granted vest and settle on each of the first, second, third and fourth anniversaries of the grant date.      
2012 Equity Incentive Plan | Employee                    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                    
Restricted stock units granted 34,388   7,582              
Fair Value per unit $ 14.54   $ 13.19              
Restricted stock units\non-qualified stock options, granted description             Twenty-five percent of the RSUs granted vest and settle on each of the first, second, third and fourth anniversaries of the grant date.      
2012 Equity Incentive Plan | Board of Directors                    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                    
Restricted stock units granted     3,000              
Fair Value per unit     $ 13.19              
Restricted stock units\non-qualified stock options, granted description             One hundred percent of the RSUs granted vested and settled on the first anniversary of the grant date.      
2012 Equity Incentive Plan | First Anniversary                    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                    
Restricted stock, vesting percentage     25.00% 25.00%            
2012 Equity Incentive Plan | First Anniversary | Employee                    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                    
Restricted stock, vesting percentage 25.00%   25.00%              
2012 Equity Incentive Plan | First Anniversary | Board of Directors                    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                    
Restricted stock, vesting percentage     100.00%              
2012 Equity Incentive Plan | Second Anniversary                    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                    
Restricted stock, vesting percentage     25.00% 25.00%            
2012 Equity Incentive Plan | Second Anniversary | Employee                    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                    
Restricted stock, vesting percentage 25.00%   25.00%              
2012 Equity Incentive Plan | Third Anniversary                    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                    
Restricted stock, vesting percentage     25.00% 25.00%            
2012 Equity Incentive Plan | Third Anniversary | Employee                    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                    
Restricted stock, vesting percentage 25.00%   25.00%              
2012 Equity Incentive Plan | Fourth Anniversary                    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                    
Restricted stock, vesting percentage     25.00% 25.00%            
2012 Equity Incentive Plan | Fourth Anniversary | Employee                    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                    
Restricted stock, vesting percentage 25.00%   25.00%