Derivative Instruments and Hedging Activities (Details) (Interest Rate Swap, USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2013
Derivative
Derivatives, Expected net loss to be transferred from accumulated OCI to earnings within 12 months	$ 12.6
Swaps Effective February 2012
Derivative
Notional Amount of Interest Rate Derivatives	950.0
Derivative, Weighted Average Fixed Interest Rate	4.908%
Derivative, Maturity Date	Feb. 01, 2014
Swaps Effective April 2011
Derivative
Notional Amount of Interest Rate Derivatives	450.0
Derivative, Weighted Average Fixed Interest Rate	5.242%
Derivative, Maturity Date	Apr. 15, 2014
Designated as Hedging Instrument
Derivative
Derivative, Net Liability Position, Aggregate Fair Value	$ 12.6

The aggregate fair value amounts of derivative instruments that contain credit-risk-related contingent features that are in a net liability position at the end of the reporting period. For nonderivative instruments that are designated and qualify as hedging instruments, the fair value amounts are the carrying value of the nonderivative hedging instrument, including the adjustment for the foreign currency transaction gain (loss) on that instrument.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4H

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624258-113959

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 44D

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant