Organization (Details) (USD $) In Thousands, except Share data, unless otherwise specified | 0 Months Ended | 9 Months Ended | |
|---|---|---|---|
Mar. 24, 2010 | Sep. 30, 2011 | Sep. 30, 2010 | |
| Organization [Line Items] | |||
| Number of global network locations in which company delivers services | 51 | ||
| Number of countries in which company delivers services | 17 | ||
| Number of shares issued in offering | 38,640,000 | ||
| Secondary offering price per common share | $ 15 | ||
| Additional common shares subscribed by underwriters | 5,040,000 | ||
| Secondary offering expenses | $ 591 | $ (591) | |
General Electric Company [Member] | |||
| Organization [Line Items] | |||
| Percent of ownership held | 9.10% | ||