Derivative Instruments and Hedging Activities (Narrative) (Details) (USD $)	1 Months Ended	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2011	Jun. 30, 2011
Derivative Instruments and Hedging Activities
Discontinuation of Cash Flow Hedge			A $500 million interest rate swap was dedesignated in conjunction with the repayment of the $500 million term loan
Repayment of term loan	$ 500,000,000	$ 500,000,000	$ 500,000,000
Recognized non-cash charge related to repayment of term loan			29,800,000
Interest rate cash flow hedge gain to be reclassified to interest expense during the next twelve months	100,000.0	100,000.0	100,000.0
Fair value of derivatives in a net liability position	29,600,000	29,600,000	29,600,000
Aggregate termination value to settle obligations	$ 29,600,000	$ 29,600,000	$ 29,600,000

The aggregate fair value of assets needed to immediately settle the derivative instruments with credit-risk-related contingent features if the credit-risk-related contingent features were triggered at the end of the reporting period.

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

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- Definition

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 or loss on that instrument.

+ References

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

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- Definition

Description of discontinued cash flow hedge relationships, including identification of hedged items and hedging instruments. Includes reasons for the discontinuation of the cash flow hedge and the effects of the discontinuation on the financial statements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Paragraph n
-Subparagraph 5
-Article 4

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The estimated net amount of unrealized gains (losses) on interest rate cash flow hedges as of the balance sheet date expected to be reclassified to earnings within the next twelve months.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 45
-Subparagraph b(2)

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The amount of loss reclassified into earnings in the period when 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.

+ References

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)

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- Definition

The cash outflow from the payment of uncollateralized debt obligation (where debt is not backed by the pledge of collateral).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 18

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 20
-Subparagraph b

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