Comprehensive Income/(Loss) - Components of Accumulated Other Comprehensive Income (Parenthetical) (Detail) |
3 Months Ended | |
|---|---|---|
Mar. 31, 2018 |
Mar. 31, 2017 |
|
| Statement of Comprehensive Income [Abstract] | ||
| Percentage of Federal and State income tax rate | 23.00% | 37.00% |