Income Tax Matters, Textuals (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Income tax provision	$ 11.7	$ 13.2	$ 19.9	$ 29.5
Effective tax rate			27.70%	38.30%
(Decrease) increase in unrecognized tax benefits, including interest and penalties			(7.2)	0.4
(Decrease) increase in effective tax rate due to unrecognized tax benefits, including interest and penalty			(10.00%)	0.50%
Refund adjustment from settlement with Canada Revenue Agency	7.7		7.7
Gross unrecognized tax benefits	8.6		8.6		15.7
Unrecognized tax benefits that would impact effective tax rate	7.5		7.5		14.6
Reduction in gross unrecognized tax benefits	$ 3.4		$ 3.4
Expected period which gross unrecognized tax benefits to be reduced	12 months		12 months