Long-Term Debt (Details) $ in Millions	1 Months Ended	12 Months Ended
	Dec. 31, 2014 USD ($)	Jan. 31, 2018 USD ($) item	Jan. 31, 2017 USD ($)	May 19, 2015 USD ($)	Dec. 16, 2014 USD ($)
Debt Instrument [Line Items]
Long-term debt		$ 1,184.6	$ 1,182.0
Long term debt outstanding		1,200.0
Revolving Credit Facility
Debt Instrument [Line Items]
Amount outstanding		0.0	0.0
Revolving credit facility				$ 750.0	$ 500.0
Current borrowing capacity		$ 744.2
Number of maintenance financial covenants | item		0
Outstanding letter of credit amount		$ 5.8
Senior Unsecured Notes 5.875 Percent Due 2022
Debt Instrument [Line Items]
Senior unsecured notes	$ 1,200.0	1,200.0	1,200.0
Less unamortized original issue discount and debt issue costs		15.4	18.0
Senior unsecured notes net of unamortized original issue discount and debt issue costs		$ 1,184.6	$ 1,182.0
Debt, interest rate		5.875%	5.875%
Long term debt outstanding			$ 1,200.0
Proceeds from the issue of Notes	1,172.1
Amount distributed to former parent from the proceeds	750.0
Proceeds net of distribution to former parent	$ 422.1