Acquisitions (Narrative) (Details) (USD $) In Thousands	9 Months Ended	3 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Jun. 30, 2010 Camiant [Member]	Jun. 30, 2010 Blueslice [Member]
Business Acquisition [Line Items]
Acquisition of companies for cash consideration, total	$ 0	$ 161,953	$ 127,000	$ 35,000

The cash outflow associated with the acquisition of a business, net of the cash acquired from the purchase.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 15, 17

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 13

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3213-108585

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Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration