Description of Business and Summary of Significant Accounting Policies Revenue Recognition (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Operating revenue	$ 128,643,000	$ 92,800,000	$ 361,499,000	$ 259,290,000
Cost of Goods and Services Sold	42,963,000	34,937,000	126,113,000	91,056,000
Revenue, Net, Increase (Decrease)	35,843,000		102,209,000
Capitalized Contract Costs, net, Current	844,000		844,000
Capitalized Contract Costs, net, Noncurrent	1,300,000		1,300,000
United States
Disaggregation of Revenue [Line Items]
Operating revenue	48,395,000	52,603,000	146,697,000	157,682,000
Revenue, Net, Increase (Decrease)			(11,000,000)
Canada
Disaggregation of Revenue [Line Items]
Operating revenue	1,267,000	1,827,000	4,323,000	5,969,000
Revenue, Net, Increase (Decrease)			(1,600,000)
Latin America
Disaggregation of Revenue [Line Items]
Operating revenue	4,586,000	6,268,000	15,141,000	14,486,000
Australia
Disaggregation of Revenue [Line Items]
Operating revenue	8,576,000	8,575,000	26,803,000	25,091,000
Revenue, Net, Increase (Decrease)			1,700,000
SINGAPORE
Disaggregation of Revenue [Line Items]
Operating revenue	1,731,000	1,368,000	5,871,000	4,493,000
New Zealand
Disaggregation of Revenue [Line Items]
Operating revenue	454,000	462,000	1,467,000	1,485,000
India
Disaggregation of Revenue [Line Items]
Operating revenue	56,631,000	17,509,000	139,985,000	37,508,000
Revenue, Net, Increase (Decrease)			102,500,000
Europe
Disaggregation of Revenue [Line Items]
Operating revenue	3,854,000	4,188,000	11,726,000	12,576,000
Dubai [Member]
Disaggregation of Revenue [Line Items]
Operating revenue	319,000	0	694,000	0
INDONESIA
Disaggregation of Revenue [Line Items]
Operating revenue	1,683,000	0	5,052,000	0
PHILIPPINES
Disaggregation of Revenue [Line Items]
Operating revenue	1,147,000	0	3,740,000	0
Exchanges [Member]
Disaggregation of Revenue [Line Items]
Operating revenue	106,853,000	64,130,000	290,292,000	177,117,000
Broker Systems [Member]
Disaggregation of Revenue [Line Items]
Operating revenue	3,414,000	3,715,000	10,720,000	11,098,000
RCS [Member]
Disaggregation of Revenue [Line Items]
Operating revenue	18,066,000	24,265,000	59,340,000	68,780,000
Carrier Systems [Member]
Disaggregation of Revenue [Line Items]
Operating revenue	310,000	$ 690,000	1,147,000	$ 2,295,000
Accounting Standards Update 2014-09 Adjustments
Disaggregation of Revenue [Line Items]
Operating revenue	32,000		(592,000)
Cost of Goods and Services Sold	$ (2,000)		$ (122,000)