Property and Equipment - Property and Equipment Schedule (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property and equipment	$ 335,913	$ 334,793
Less accumulated depreciation and amortization	(202,513)	(189,317)
Property and equipment, net	133,400	145,476
Land
Property, Plant and Equipment [Line Items]
Property and equipment	205	205
Building
Property, Plant and Equipment [Line Items]
Property and equipment	605	605
Computer equipment, furniture, and office equipment
Property, Plant and Equipment [Line Items]
Property and equipment	61,093	61,193
Computer software purchased
Property, Plant and Equipment [Line Items]
Property and equipment	31,181	31,218
Capitalized internal-use software
Property, Plant and Equipment [Line Items]
Property and equipment	237,792	227,137
Tenant improvements
Property, Plant and Equipment [Line Items]
Property and equipment	$ 5,037	$ 14,435