Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Supplemental disclosure of cash flow information:
Interest paid	$ 13.5	$ 12.2
Non-cash investing and financing activities:
Stock repurchases not yet settled (accrued in accounts payable)	0.3	0.2
Unpaid purchases of property and equipment	$ 4.4	$ 1.8