Supplemental Cash Flows Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Supplemental Cash Flows Information [Abstract]
Interest Paid	$ 33.1	$ 33.1	$ 26.6
Cash paid for income taxes	37.4	42.0	49.5
Capital Expenditures Incurred but Not yet Paid	0.4	0.6	0.6
Tax Benefit from Stock Options Exercised	$ 5.4	$ 7.5	$ 10.2