Computer Hardware and Other Property, Net (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Total computer hardware and other property	$ 52,239		$ 52,239		$ 41,528
Accumulated depreciation	(27,915)		(27,915)		(23,486)
Total computer hardware and other property, net	24,324		24,324		18,042
Depreciation	2,904	$ 2,131	5,233	$ 4,182
Computer hardware
Property, Plant and Equipment [Line Items]
Total computer hardware and other property	27,928		27,928		24,620
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total computer hardware and other property	16,889		16,889		12,496
Furniture, fixtures and equipment
Property, Plant and Equipment [Line Items]
Total computer hardware and other property	$ 7,422		$ 7,422		$ 4,412