Derivative Instruments And Hedging Activities (Narrative) (Details) (USD $) In Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2011	Dec. 31, 2010
Purchase [Member]
Derivative [Line Items]
Notional amounts of the outstanding foreign currency forward contracts	$ 13.2	$ 13.2	$ 8.6
Average notional amount of foreign currency derivatives	12.7	13.9
Sell [Member]
Derivative [Line Items]
Notional amounts of the outstanding foreign currency forward contracts	33.2	33.2	56.8
Average notional amount of foreign currency derivatives	$ 31.9	$ 38.0