Business Combinations (Pro Forma) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Business Acquisition, Pro Forma Information
Revenue	$ 74,608	$ 66,813	$ 218,248	$ 195,278
Net Income (Loss) Attributable to Parent	$ 24,067	$ 20,232	$ 69,218	$ 57,604
Basic EPS	$ 0.74	$ 0.59	$ 2.12	$ 1.65
Diluted EPS	$ 0.74	$ 0.59	$ 2.10	$ 1.63
Revenue, Net, Increase (Decrease)	$ 7,795
Revenue, Net, Increase (Decrease), Percentage	11.70%
Parent, Via Media and PB Systems Combined [Member]
Business Acquisition, Pro Forma Information
Revenue, pro forma	$ 74,608	$ 69,854	$ 224,534	$ 211,013
Net income, pro forma	$ 24,067	$ 19,574	$ 68,249	$ 56,206
Basic EPS, pro forma	$ 0.74	$ 0.57	$ 2.09	$ 1.61
Diluted EPS, pro forma	$ 0.74	$ 0.57	$ 2.07	$ 1.59
Business Acquisition, Pro Forma Revenue, Increase (Decrease), Percentage	6.80%		6.40%
Impact of Currency Rates [Member]
Business Acquisition, Pro Forma Information
Revenue, Net, Increase (Decrease)	$ (300)		$ (3,300)