Derivative Instruments And Hedging Activities (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011
Derivative Instruments And Hedging Activities [Abstract]
Notional value of foreign exchange contracts	$ 172		$ 155
Net cash outflow/inflow from settlement of derivative contracts	$ 5.8	$ 5.5

Aggregate notional amount of foreign currency exchange rate derivatives. Notional amount refers to the number of currency units specified in the foreign currency derivative contract.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Notional Amount

-URI http://asc.fasb.org/extlink&oid=6519104

Name:	us-gaap_NotionalAmountOfForeignCurrencyDerivatives
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant