Acquisitions (Details 2) (USD $) In Thousands, unless otherwise specified	1 Months Ended
Nov. 30, 2011 BTS	Nov. 30, 2011 BTS Backlog	Nov. 30, 2011 BTS Technology	Nov. 30, 2011 BTS Customer contracts / relationships	Nov. 30, 2011 BTS Other purchased intangible assets	Nov. 30, 2011 BTS Other purchased intangible assets Minimum	Nov. 30, 2011 BTS Other purchased intangible assets Maximum	Jan. 31, 2011 MET	Jan. 31, 2011 MET Technology	Jan. 31, 2011 MET Customer contracts / relationships	Jan. 31, 2011 MET Other purchased intangible assets	Jan. 31, 2011 MET Other purchased intangible assets Minimum	Jan. 31, 2011 MET Other purchased intangible assets Maximum
Purchased intangible assets
Estimated Useful Life		3 years	6 years	6 years		5 years	7 years		6 years	6 years		3 years	7 years
Amount of purchased intangible assets	$ 1,100	$ 330	$ 290	$ 250	$ 230			$ 1,620	$ 570	$ 500	$ 550

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (a)(3)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16265-109275

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration