Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|---|
Sep. 30, 2018 |
Sep. 30, 2017 |
Sep. 30, 2018 |
Sep. 30, 2017 |
Dec. 31, 2017 |
|
| Income Tax Disclosure [Abstract] | |||||
| Income tax (benefit) provision | $ (921) | $ (4,258) | $ (4,753) | $ 129,933 | |
| Statutory tax rate | 21.00% | 35.00% | 21.00% | 35.00% | 35.00% |
| NOLs, limitations on use | The Exchange Transactions triggered a cumulative change in ownership of our common stock by more than 50% under Section 382 of the Internal Revenue Code as of March 22, 2017. This established an annual limitation on the usage of our pre-change net operating losses (“NOLs”) in the future. | ||||
| Write-off deferred tax assets | $ 139,090 | ||||