Derivative Instruments and Hedging Activities Disclosure (Details) (Accrued Liabilities [Member], USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Accrued Liabilities [Member]
Derivative instrument fair values in the Statement of Financial Position:
Derivatives designated as hedging instruments	$ 6,532	$ 3,413
Derivatives not designated as hedging instruments	$ 451	$ 564

Fair value of a derivative liability (or nonderivative instrument) that is designated and qualifies as a hedging instrument, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 205G

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 44C
-Subparagraph a
-Clause 1

Name:	us-gaap_DerivativeLiabilityDesignatedAsHedgingInstrumentFairValue
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant