Non-Qualified Deferred Compensation Plan Non-Qualified Deferred Compensation Plan (Details) (USD $) In Millions	Jun. 30, 2011	Dec. 31, 2010
Non Qualified Deferred Compensation Plan [Abstract]
Deferred Compensation Liability, Current and Noncurrent	$ 37.3	$ 35.0

Name:

us-gaap_DeferredCompensationLiabilityCurrentAndNoncurrent

Namespace Prefix:

us-gaap

Data Type:

xbrli:monetaryItemType

Balance Type:

credit

Period Type:

instant