Supplemental Cash Flow Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Supplemental disclosure of cash flow information:
Interest paid			$ 5.1	$ 5.1
Income taxes paid	0.3	0.9	0.5	1.0
Supplemental disclosure of non-cash transactions:
Non-cash capital expenditures			$ 2.1	$ 0.7