Employee Benefit Plans - Summary of Estimated Contributions (Detail) |
12 Months Ended |
---|---|
Dec. 31, 2016
USD ($)
| |
Supplemental Employee Retirement Plan [Member] | |
Defined Contribution Plan Disclosure [Line Items] | |
Estimated contributions for 2017 | $ 422,656 |
Postretirement Benefits [Member] | |
Defined Contribution Plan Disclosure [Line Items] | |
Estimated contributions for 2017 | $ 113,268 |