|
Fair Value (Details) (USD $)
In Millions, unless otherwise specified |
Jun. 30, 2012
|
Dec. 31, 2011
|
|---|---|---|
|
DTA Bond [Member]
|
||
| DTA bonds [Abstract] | ||
| Carrying value | $ 43.2 | $ 43.2 |
| Fair value | 44.1 | 44.0 |
|
Unsecured Notes Issued in a Private Placement [Member]
|
||
| DTA bonds [Abstract] | ||
| Carrying value | 100.0 | 100.0 |
| Fair value | 108.6 | 106.4 |
|
Mutual funds [Member]
|
||
| Investments in Available-for-sale Securities [Line Items] | ||
| Cost | 7.0 | 16.9 |
| Gross Unrealized Gains | 1.5 | 3.1 |
| Fair Value | $ 8.5 | $ 20.0 |