Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Performance Stock Units - Additional Information (Detail)

v3.19.3
Stock-Based Compensation - Performance Stock Units - Additional Information (Detail) - USD ($)
1 Months Ended 3 Months Ended 9 Months Ended
Jun. 30, 2019
Sep. 30, 2019
Sep. 30, 2018
Sep. 30, 2019
Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Performance stock, shares granted   2,074,654   2,074,654  
Stock-based compensation expense   $ 2,705,000 $ 589,000 $ 6,565,000 $ 3,016,000
2017 Omnibus Plan [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Vesting period       6 years  
Performance stock, shares granted   2,585,610   2,585,610  
Performance Stock Units [Member] | 2017 Omnibus Plan [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Vesting period 3 years        
Increase in common stock starting price $ 12.48        
Stock-based compensation expense   $ 114,000   $ 114,000  
Unrecognized stock-based compensation expense related to performance stock units   $ 2,100   $ 2,100  
Unrecognized stock-based compensation expense, expected recognition weighted-average period       57 months  
Performance Stock Units [Member] | Tranche One [Member] | 2017 Omnibus Plan [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Vesting percentage 50.00%        
Performance Stock Units [Member] | Tranche Two [Member] | 2017 Omnibus Plan [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Vesting percentage 100.00%        
Performance Stock Units [Member] | Tranche Three [Member] | 2017 Omnibus Plan [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Vesting percentage 120.00%        
Performance Stock Units [Member] | Three Executive Officers [Member] | 2017 Omnibus Plan [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Performance stock, shares granted 311,667