Supplemental Cash Flow Information (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Supplemental Cash Flow Elements [Abstract]
Payments of interest and commitment fees	$ 41.5	$ 32.9	$ 25.1
Capitalized interest	3.9	0.1
Tax refunds received	(0.3)	(0.1)
Cash paid for income taxes			2.4
Incurred liabilities for fixed and intangible asset additions	$ 14.1	$ 2.0	$ 2.6