Property and Equipment - Summary of Property and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Accumulated depreciation and amortization	$ (99,178)	$ (89,275)
Property and equipment, net	43,312	46,431
Property and equipment, gross
Property, Plant and Equipment [Line Items]
Property and equipment, gross	138,236	130,160
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	27,712	28,789
Website and software development costs
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 86,839	75,573
Website and software development costs | Minimum
Property, Plant and Equipment [Line Items]
Useful Lives (Years)	3 years
Website and software development costs | Maximum
Property, Plant and Equipment [Line Items]
Useful Lives (Years)	5 years
Computer and office equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 14,758	16,175
Computer and office equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful Lives (Years)	3 years
Computer and office equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful Lives (Years)	5 years
Software
Property, Plant and Equipment [Line Items]
Useful Lives (Years)	3 years
Property and equipment, gross	$ 1,607	1,869
Furniture
Property, Plant and Equipment [Line Items]
Useful Lives (Years)	7 years
Property and equipment, gross	$ 7,320	7,754
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 4,254	$ 5,546