Income and Other Taxes - Schedule of Income from Operations Before Provision for Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Domestic	$ 168.7	$ 114.4	$ 76.0
Foreign	(0.6)	(2.3)	0.5
Income from operations before provision for income taxes	$ 168.1	$ 112.1	$ 76.5