Property And Equipment, Net (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Property And Equipment, Net [Abstract]
Depreciation expense	$ 175.8	$ 161.4	$ 150.6
Non-cash capital expenditures	$ 7.2	$ 4.7