U.K. Pension Plan (Details) (Foreign Pension Plans, Defined Benefit [Member], USD $) In Millions, unless otherwise specified | 3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2011 | Sep. 30, 2010 | Sep. 30, 2011 | Sep. 30, 2010 | |
Foreign Pension Plans, Defined Benefit [Member] | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Service cost for benefits earned during the year | $ 0 | $ 0 | $ 0 | $ 0 |
| Interest cost on projected benefit obligation | 1.0 | 1.0 | 2.9 | 2.9 |
| Expected return on plan assets | (0.9) | (0.9) | (2.7) | (2.7) |
| Net amortization | 0.5 | 0.5 | 1.5 | 1.5 |
| Net pension expense | 0.6 | 0.6 | 1.7 | 1.7 |
| Company contributions to pension plan | 2.7 | |||
| Number of members who elected to transfer assets out of Plan | 14 | |||
| Enhanced transfer value expense | $ 1.2 | $ 2.3 | ||