Acquisitions - Summary of Preliminary Acquisition Consideration and the Related Fair Values of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands			6 Months Ended
	Jun. 01, 2018	May 31, 2017	Jun. 30, 2018
Ahalogy
Business Acquisition [Line Items]
Purchase Consideration	$ 36,432
Net Tangible Assets Acquired/ (Liabilities Assumed)	2,693
Identifiable Intangible Assets	11,580
Goodwill	$ 22,159		$ 22,159
Goodwill Deductible for Taxes	Not Deductible
Acquisition Related Expenses	$ 561
Crisp Media, Inc
Business Acquisition [Line Items]
Purchase Consideration		$ 51,904
Net Tangible Assets Acquired/ (Liabilities Assumed)		5,893
Identifiable Intangible Assets		9,400
Goodwill		$ 36,611
Goodwill Deductible for Taxes		Not Deductible
Acquisition Related Expenses		$ 1,504