Acquisitions (Components of Intangible Assets) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended		0 Months Ended
Dec. 31, 2013 Technology [Member]	Dec. 31, 2012 Technology [Member]	Dec. 31, 2013 Trade Names [Member]	Dec. 31, 2012 Trade Names [Member]	Dec. 31, 2013 Non-compete Agreements [Member]	Dec. 31, 2012 Non-compete Agreements [Member]	Nov. 09, 2012 Engage [Member]	Nov. 09, 2012 Engage [Member] Technology [Member]	Nov. 09, 2012 Engage [Member] Trade Names [Member]	Nov. 09, 2012 Engage [Member] Customer Relationships [Member]	Nov. 09, 2012 Engage [Member] Non-compete Agreements [Member]
Business Acquisition [Line Items]
Weighted Average Useful Life (months)	3 years 9 months 18 days	3 years 9 months 18 days	2 years 8 months 12 days	2 years 8 months 12 days	1 year 2 months 12 days	1 year 2 months 12 days		36 months	12 months	48 months	12 months
Intangible assets							$ 3,600	$ 768	$ 95	$ 2,661	$ 76

The amount of acquisition cost of a business combination allocated to an identifiable intangible asset that will be amortized.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 51

-Subparagraph e

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 52

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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_BusinessAcquisitionPurchasePriceAllocationAmortizableIntangibleAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant