Acquisitions (Components of Intangible Assets) (Details) - USD ($) $ in Thousands			6 Months Ended	12 Months Ended
	Nov. 07, 2014	Jun. 02, 2014	Jun. 30, 2015	Dec. 31, 2014
Contact At Once! [Member]
Business Acquisition [Line Items]
Intangible assets	$ 20,400
Synchronite, LLC [Member]
Business Acquisition [Line Items]
Intangible assets		$ 1,451	$ 1,500
Technology [Member]
Business Acquisition [Line Items]
Weighted average useful life			5 years 3 months 18 days	5 years 3 months 18 days
Technology [Member] | Contact At Once! [Member]
Business Acquisition [Line Items]
Weighted average useful life	96 months
Intangible assets	$ 8,400
Technology [Member] | Synchronite, LLC [Member]
Business Acquisition [Line Items]
Weighted average useful life		120 months
Intangible assets		$ 1,082
Trade Names [Member]
Business Acquisition [Line Items]
Weighted average useful life			2 years 9 months 12 days	2 years 9 months 12 days
Trade Names [Member] | Contact At Once! [Member]
Business Acquisition [Line Items]
Weighted average useful life	12 months
Intangible assets	$ 500
Trade Names [Member] | Synchronite, LLC [Member]
Business Acquisition [Line Items]
Weighted average useful life		48 months
Intangible assets		$ 62
Customer Relationships [Member] | Contact At Once! [Member]
Business Acquisition [Line Items]
Weighted average useful life	120 months
Intangible assets	$ 10,700
Customer Relationships [Member] | Synchronite, LLC [Member]
Business Acquisition [Line Items]
Weighted average useful life		84 months
Intangible assets		$ 247
Non-compete Agreements [Member]
Business Acquisition [Line Items]
Weighted average useful life			2 years 3 months 12 days	2 years 3 months 12 days
Non-compete Agreements [Member] | Contact At Once! [Member]
Business Acquisition [Line Items]
Weighted average useful life	36 months
Intangible assets	$ 800
Non-compete Agreements [Member] | Synchronite, LLC [Member]
Business Acquisition [Line Items]
Weighted average useful life		36 months
Intangible assets		$ 60