Income Taxes - Additional Information (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | |||
|---|---|---|---|---|---|
Jun. 30, 2016 |
Jun. 30, 2015 |
Jun. 30, 2016 |
Jun. 30, 2015 |
Dec. 31, 2015 |
|
| Income Tax Disclosure [Abstract] | |||||
| Effective income tax rates | 5.20% | (11.10%) | 2.30% | (5.70%) | |
| Estimated useful life for amortization of tax expense | 30 years | ||||
| Prepaid tax asset, net of amortization | $ 278.6 | $ 278.6 | $ 190.1 | ||
| Unrecognized Tax Benefits | 1.5 | 1.5 | 1.5 | ||
| Unrecognized Tax Benefits Income Tax Penalties And Interest Accrued | $ 0.3 | $ 0.3 | $ 0.3 | ||