Employee Benefit Plans - Summary of Estimated Contributions (Detail) |
Dec. 31, 2017
USD ($)
|
---|---|
Pension Plan [Member] | |
Defined Contribution Plan Disclosure [Line Items] | |
Estimated contributions | $ 200,000 |
Supplemental Employee Retirement Plan [Member] | |
Defined Contribution Plan Disclosure [Line Items] | |
Estimated contributions | $ 505,169 |