Supplemental Cash Flow Information (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Supplemental Cash Flow Information
Interest paid	$ 0.7	$ 0.8
Income taxes paid	11.1	11.3
Increase (decrease) in accounts payable and accrued liabilities for changes in unpaid capital expenditures	$ (1.0)	$ 1.4