Deferred Compensation Plan (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010
Deferred Compensation Plan (Details) [Abstract]
Maximum deferral % of base compensation allowed to participants of deferred compensation plan	50.00%
Maximum deferral % of bonus compensation allowed to participants of deferred compensation plan	100.00%
Deferred compensation plan liability	$ 2.9	$ 2.0

Aggregate carrying value as of the balance sheet date of the liabilities for all deferred compensation arrangements. Represents currently earned compensation under compensation arrangements that is not actually paid until a later date.

No definition available.

Name:	us-gaap_DeferredCompensationLiabilityCurrentAndNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant