Financial Instruments (Details Textual) (USD $)	3 Months Ended	12 Months Ended		1 Months Ended	12 Months Ended
Sep. 30, 2010	Dec. 31, 2010	Dec. 31, 2011	Dec. 31, 2007 Cash flow hedging [Member]	Dec. 31, 2010 Cash flow hedging [Member] Interest Rate Swap [Member] Miscellaneous Expense [Member]
Financial Instruments (Textual) [Abstract]
Fixed Interest Rate to Conversion of variable-rate term loan facility to fixed interest rate				$ 150,000,000
Loss on settlement of interest rate swaps	6,800,000	6,849,000			6,800,000
Notional amount of foreign currency forward contract		$ 187,300,000	$ 249,300,000

The amount of net gain (loss) reclassified into earnings when interest rate cash flow hedge is discontinued because it is probable that the original forecasted transactions will not occur by the end of the original period or an additional two month time period.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 45

-Subparagraph b(4)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (e)

-URI http://asc.fasb.org/extlink&oid=6887037&loc=d3e80748-113994

Name:	us-gaap_GainLossOnDiscontinuationOfInterestRateCashFlowHedgeDueToForecastedTransactionProbableOfNotOccurringNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration