|
Quarterly Financial Data- Unaudited (Details) (USD $)
In Thousands, except Per Share data, unless otherwise specified |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
|
Dec. 31, 2011
|
Sep. 30, 2011
|
Jun. 30, 2011
|
Mar. 31, 2011
|
Dec. 31, 2010
|
Sep. 30, 2010
|
Jun. 30, 2010
|
Mar. 31, 2010
|
Dec. 31, 2011
|
Dec. 31, 2010
|
Dec. 31, 2009
|
|
| Quarterly results of operations | |||||||||||
| Total revenue | $ 783,738 | $ 762,550 | $ 744,397 | $ 723,839 | $ 735,899 | $ 717,548 | $ 699,761 | $ 663,784 | $ 3,014,524 | $ 2,816,992 | $ 2,472,638 |
| Cost of services | (299,719) | (277,360) | (273,331) | (270,689) | (291,699) | (280,545) | (266,121) | (260,867) | |||
| Income from operations | 154,475 | 184,488 | 172,982 | 164,172 | 71,571 | 143,069 | 125,634 | 125,140 | 676,117 | 465,414 | 228,326 |
| Net income (loss) | $ 71,336 | $ 104,185 | $ 173,319 | $ 78,121 | $ (81,444) | $ 67,629 | $ 15,272 | $ 41,598 | $ 426,961 | $ 43,055 | $ (352,038) |
| Net income (loss) per common share- basic | $ 0.02 | $ 0.03 | $ 0.05 | $ 0.02 | $ (0.02) | $ 0.02 | $ 0.01 | $ 0.11 | $ 0.01 | $ (0.15) | |
| Net income (loss) per common share- diluted | $ 0.01 | $ 0.02 | $ 0.03 | $ 0.01 | $ (0.02) | $ 0.01 | $ 0.01 | $ 0.07 | $ 0.01 | $ (0.15) | |
| X | ||||||||||
|
- Definition
Total costs related to services rendered by an entity during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
|
- Definition
The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
|
- Definition
The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
|
- Definition
The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
|
- Definition
The net result for the period of deducting operating expenses from operating revenues. No definition available.
|
| X | ||||||||||
|
- Details
|
| X | ||||||||||
|
- Definition
Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|