Business Acquisitions (Narrative) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020 USD ($)
Business Acquisition [Line Items]
Revenues contributed through acquisitions	$ 5,900
Total consideration of transactions	39,100
Increase (decrease) in goodwill from adjustment under purchase accounting	7,591
Goodwill	23,817
Expected income tax deductible amount	22,600
Voice, Backup, Security and CPP
Business Acquisition [Line Items]
Increase (decrease) in goodwill from adjustment under purchase accounting	(2,100)
Digital Media
Business Acquisition [Line Items]
Increase (decrease) in goodwill from adjustment under purchase accounting	$ 9,700