Property and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 121,208	$ 112,533
Less: accumulated depreciation	(72,776)	(68,798)
Total	48,432	43,735
Computer equipment and software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	77,881	79,161
Software Development [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	28,835	19,240
Furniture, equipment and building improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 14,492	$ 14,132