Summary Of Significant Accounting Policies (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 years	Dec. 31, 2010	Dec. 31, 2009
Summary Of Significant Accounting Policies [Abstract]
Typical minimum amortized life assigned to identifiable intangible assets (in years)	2
Typical maximum amortized life assigned to identifiable intangible assets (in years)	5
Provision for workers' compensation claims threshold	$ 0.5
Goodwill impairment loss recognized	$ 0	$ 0	$ 0