Acquisitions, Contingent Consideration by Acquisition (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Other current liabilities [Member]
Business Acquisition, Contingent Consideration [Line Items]
Contingent Consideration, Liability	$ 2,842	$ 492
Other non current liabilities [Member]
Business Acquisition, Contingent Consideration [Line Items]
Contingent Consideration, Liability	1,948	409
Hyperspring, LLC [Member] | Other current liabilities [Member]
Business Acquisition, Contingent Consideration [Line Items]
Contingent Consideration, Liability	2,152	0
Hyperspring, LLC [Member] | Other non current liabilities [Member]
Business Acquisition, Contingent Consideration [Line Items]
Contingent Consideration, Liability	1,948	0
IntelliQlik, LLC [Member] | Other current liabilities [Member]
Business Acquisition, Contingent Consideration [Line Items]
Contingent Consideration, Liability	213	0
EnVision Systems, Inc. [Member] | Other current liabilities [Member]
Business Acquisition, Contingent Consideration [Line Items]
Contingent Consideration, Liability	477	492
EnVision Systems, Inc. [Member] | Other non current liabilities [Member]
Business Acquisition, Contingent Consideration [Line Items]
Contingent Consideration, Liability	$ 0	$ 409