Income Taxes - Additional Information (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | |||
|---|---|---|---|---|---|
Jun. 30, 2018 |
Jun. 30, 2017 |
Jun. 30, 2018 |
Jun. 30, 2017 |
Dec. 31, 2017 |
|
| Income Tax Contingency [Line Items] | |||||
| Effective income tax rates | (6.50%) | (17.10%) | (8.40%) | (12.20%) | |
| Unrecognized tax benefits | $ 0.6 | $ 0.6 | $ 1.5 | ||
| Unrecognized tax benefits income tax penalties and interest accrued | $ 0.2 | 0.2 | 0.4 | ||
| Unrecognized tax benefits, reduction resulting from lapse of applicable statute of limitations | $ 1.1 | ||||
| State | |||||
| Income Tax Contingency [Line Items] | |||||
| Net operating loss carryforwards | 630.7 | ||||
| Net operating loss carryforwards, Year of expiration | 2024 | ||||
| Federal | |||||
| Income Tax Contingency [Line Items] | |||||
| Net operating loss carryforwards | $ 700.3 | ||||
| Net operating loss carryforwards, Year of expiration | 2028 | ||||