Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation Plans - Stock-Based Compensation Expense (Detail)

v3.21.2
Stock-Based Compensation Plans - Stock-Based Compensation Expense (Detail) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Sep. 30, 2021
Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Allocated share-based compensation expense $ 2,703 $ 2,383 $ 7,653 $ 7,551
Employee Stock Purchase Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Allocated share-based compensation expense 33 62 107 145
Restricted Stock Awards [Member] | Non-Employee Directors [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Allocated share-based compensation expense 114 120 338 493
Restricted Stock Units [Member] | Employees [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Allocated share-based compensation expense 1,731 1,413 4,932 4,583
Restricted Stock Units [Member] | Independent Contractors, Subsequent to Adoption of New Standard [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Allocated share-based compensation expense $ 825 $ 788 $ 2,276 $ 2,330