Long-Lived Assets - Summary of Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 155,982	$ 148,274
Less - accumulated depreciation	(122,866)	(112,282)
Property and equipment, net	$ 33,116	35,992
Minimum
Property Plant And Equipment [Line Items]
Property and equipment, useful lives	3 years
Maximum
Property Plant And Equipment [Line Items]
Property and equipment, useful lives	10 years
Computer equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 74,640	70,408
Computer equipment | Minimum
Property Plant And Equipment [Line Items]
Property and equipment, useful lives	3 years
Computer equipment | Maximum
Property Plant And Equipment [Line Items]
Property and equipment, useful lives	5 years
Leasehold improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 15,013	15,226
Leasehold improvements | Minimum
Property Plant And Equipment [Line Items]
Property and equipment, useful lives	5 years
Leasehold improvements | Maximum
Property Plant And Equipment [Line Items]
Property and equipment, useful lives	10 years
Operating equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 57,210	53,494
Operating equipment | Minimum
Property Plant And Equipment [Line Items]
Property and equipment, useful lives	3 years
Operating equipment | Maximum
Property Plant And Equipment [Line Items]
Property and equipment, useful lives	8 years
Furniture and fixtures
Property Plant And Equipment [Line Items]
Property and equipment, useful lives	8 years
Property and equipment, gross	$ 9,119	$ 9,146