|
Accumulated Other Comprehensive Loss (Narrative) (Details) (USD $)
|
6 Months Ended | 12 Months Ended | |||
|---|---|---|---|---|---|
|
Jun. 30, 2011
|
Dec. 31, 2010
|
Dec. 31, 2008
|
Sep. 16, 2005
|
Jul. 22, 2003
|
|
| Notional amount of interest rate swap agreements | $ 420,000,000 | $ 900,000,000 | $ 500,000,000 | ||
| Refinancing of long-term debt | 725,000,000 | 1,000,000,000 | |||
| Number of interest rate swap agreements | 3 | ||||
| Number of counterparties entered into interest rate swap agreement | 7 | ||||
| Number of tranches | 2 | ||||
| Unrealized loss, net of tax | 20,600,000 | 21,100,000 | |||
|
5.33% - Due June 30, 2027 [Member]
|
|||||
| Refinancing of long-term debt | 375,000,000 | ||||
| Interest rate of long-term debt | 5.33% | ||||
| Debt instrument maturity date | Jun. 30, 2027 | ||||
|
6.00% - Due June 30, 2032 [Member]
|
|||||
| Refinancing of long-term debt | $ 350,000,000 | ||||
| Interest rate of long-term debt | 6.00% | ||||
| Debt instrument maturity date | Jun. 30, 2032 | ||||