Fair Value Measurements (Reconciliation Using Significant Unobservable Inputs) (Details) (Fair Value, Measurements, Recurring [Member], USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value of liability at September 30, 2012	$ 12.7
Fair Value, Inputs, Level 3 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value of liability at December 31, 2011	10.3
Contingent obligation arising from acquisition	1.2
Included in operating expense	1.2
Fair value of liability at September 30, 2012	$ 12.7