Share-Based Compensation - Additional Information (Detail) - USD ($) |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2019 |
Sep. 30, 2018 |
Sep. 30, 2019 |
Sep. 30, 2018 |
|
| Disclosure of Compensation Related Costs, Share-based Payments [Abstract] | ||||
| Compensation expense in stock compensation plans | $ 247,301 | $ 317,526 | $ 1,100,000 | $ 1,400,000 |
| Income tax benefit of stock compensation plans | 51,933 | 66,680 | 233,851 | 285,578 |
| Unrecognized compensation expense related to nonvested share-based compensation granted under the plan | 1,300,000 | $ 1,300,000 | ||
| Weighted average period of unrecognized compensation expense | 1 year 6 months | |||
| Cash from option exercises | 772,969 | 217,112 | $ 1,600,000 | 695,762 |
| Tax benefit for tax deductions related to option exercises | $ 22,414 | $ 2,516 | $ 38,376 | $ 21,319 |