Supplemental Cash Flow Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Supplemental disclosure of cash flow information:
Interest paid			$ 14.0	$ 5.1
Income taxes paid	0.6	0.3	1.3	0.5
Supplemental disclosure of non-cash transactions:
Stock repurchases not yet settled (accrued in accounts payable)			0.6	0
Non-cash capital expenditures			4.4	2.1
Capital leases acquired			$ 0.2	$ 0