|
Fair Value Measurements (Narrative) (Details) (USD $)
In Millions, unless otherwise specified |
Dec. 31, 2010
|
Mar. 31, 2011
Auction Rate Securities, Sold [Member]
|
Mar. 31, 2011
Auction Rate Securities, Repurchased [Member]
|
|---|---|---|---|
| Percent amount of par value at sale | 90.00% | ||
| Auction rate securities par value | $ 50.1 | $ 8.1 | $ 42.0 |