Supplemental Cash Flow Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Supplemental disclosure of cash flow information:
Interest paid	$ 0.4	$ 0.4
Income taxes paid	0.7	0.7
Supplemental disclosure of non-cash transactions:
Stock repurchases not yet settled (accrued in accounts payable)	0	1.5
Non-cash capital expenditures	3.4	2.7
Capital leases acquired	$ 0	$ 0.1