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