Derivatives and Hedging Activities - Additional Information (Detail)	Dec. 31, 2011
Maximum remaining maturity of foreign currency derivatives	3 months

Maximum amount of time remaining before foreign currency exchange rate derivatives mature or expire.

No definition available.

Name:	us-gaap_MaximumRemainingMaturityOfForeignCurrencyDerivatives
Namespace Prefix:	us-gaap_
Data Type:	us-types:durationStringItemType
Balance Type:	na
Period Type:	instant