Description of Business and Summary of Significant Accounting Policies (Segment Reporting) (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) ProductService_Groups	Sep. 30, 2014 USD ($)
Accounting Policies [Abstract]
Total revenue, international percentage			22.70%	32.80%
Number of product/service groups | ProductService_Groups			4
Segment Reporting Information [Line Items]
Document Period End Date			Sep. 30, 2015
Operating revenue	$ 66,813	$ 50,808	$ 195,278	$ 153,688
Exchanges [Member]
Segment Reporting Information [Line Items]
Operating revenue	46,209	41,757	139,712	125,212
Broker Systems [Member]
Segment Reporting Information [Line Items]
Operating revenue	3,812	4,511	11,067	13,862
RCS [Member]
Segment Reporting Information [Line Items]
Operating revenue	15,754	3,346	41,218	10,423
Carrier Systems [Member]
Segment Reporting Information [Line Items]
Operating revenue	$ 1,038	$ 1,194	$ 3,281	$ 4,191