(Benefit) Provision for Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
(Benefit) Provision for Income Taxes
Income tax (benefit) provision	$ (4.0)	$ 10.7	$ 3.8	$ 17.8
Effective tax rates (as a percent)	(9.30%)	45.30%	4.30%	29.30%
Unrecognized tax benefits, excluding penalties and interest	$ 7.3		$ 7.3		$ 26.9
Portion of unrecognized tax benefits, which if recognized, would result in a reduction of the effective tax rate	6.4		6.4		13.0
Accrued interest and penalties related to uncertain tax positions	0.7		0.7		$ 4.7
Penalties and interest expense relating to unrecognized tax benefits	$ 0.9	$ 0.0	$ 1.5	$ 1.1