Consolidated Financial Statements (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2012
Consolidated Financial Statements [Abstract]
Prior period reclassified amounts from stock-based compensation to changes in other liabilities	$ 1.5

The amount of a reclassification adjustment made to prior period financial statement amounts.

No definition available.

Name:	us-gaap_PriorPeriodReclassificationAdjustment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration