Commitments and Contingencies (Details) (ClearPoint, USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011	Jan. 03, 2011 Maximum
ClearPoint - Acquisition
Contingent amount payable in installments			$ 2.0
Accrued contingent obligation recorded in accrued compensation	$ 0.6	$ 0.8

Amount of potential cash payments that could result from the contingent consideration arrangement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 51

-Subparagraph f

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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