Supplemental Cash Flow Information (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Supplemental disclosure of cash flow information:
Interest paid	$ 19.4	$ 10.4	$ 6.0
Income taxes paid	1.8	3.5	0.8
Supplemental disclosure of non-cash transactions:
Non-cash capital expenditures	3.4	1.8	1.7
Issuance of Nichols Promissory Note - Note 3	0	0	6.7
Capital leases acquired	$ 0.1	$ 0.3	$ 0