|
Shareholders' Equity (Details) (USD $)
|
12 Months Ended | ||
|---|---|---|---|
|
Dec. 31, 2011
|
Dec. 31, 2010
|
Dec. 31, 2009
|
|
| Shareholders' Equity [Abstract] | |||
| Stock repurchase plan, authorized amount | $ 500,000,000 | ||
| Aggregate shares repurchased under stock repurchase plan | 9,588,798 | ||
| Stock repurchased during period, value | 20,000,000 | 13,838,000 | 7,399,000 |
| Stock repurchased to date, value | $ 441,237,000 | ||
| X | ||||||||||
|
- Definition
Equity impact of the value of stock that has been repurchased to date and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock. No definition available.
|
| X | ||||||||||
|
- Definition
Number of shares that have been repurchased to date under the program. No definition available.
|
| X | ||||||||||
|
- Details
|
| X | ||||||||||
|
- Definition
Equity impact of the value of stock that has been repurchased during the period and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
|
- Definition
The amount authorized by an entity's Board of Directors under a stock repurchase plan. No definition available.
|