Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Supplemental disclosure of cash flow information:
Interest paid	$ 6.7	$ 13.5
Non-cash investing and financing activities:
Stock repurchases not yet settled (accrued in accounts payable)	0.2	0.3
Unpaid purchases of property and equipment	$ 2.4	$ 4.4