Goodwill and Intangible Assets - Schedule of Finite-lived Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Finite-Lived Intangible Assets [Line Items]
Gross	$ 1,047,884	$ 1,044,259
Accumulated Amortization	(1,023,616)	(1,009,544)
Total	$ 24,268	$ 34,715
Weighted average remaining amortization period in years (in years)	1 year 6 months	1 year 9 months 18 days
Client relationships
Finite-Lived Intangible Assets [Line Items]
Gross	$ 794,774	$ 796,213
Accumulated Amortization	(779,260)	(771,475)
Total	$ 15,514	$ 24,738
Weighted average remaining amortization period in years (in years)	1 year 6 months	1 year 9 months 18 days
Trademarks and domain names
Finite-Lived Intangible Assets [Line Items]
Gross	$ 223,158	$ 223,206
Accumulated Amortization	(218,567)	(215,639)
Total	$ 4,591	$ 7,567
Weighted average remaining amortization period in years (in years)	1 year 10 months 24 days	1 year 8 months 12 days
Patented technologies
Finite-Lived Intangible Assets [Line Items]
Gross	$ 19,600	$ 19,600
Accumulated Amortization	(19,600)	(19,600)
Total	$ 0	$ 0
Weighted average remaining amortization period in years (in years)	0 years	0 years
Covenants not to compete
Finite-Lived Intangible Assets [Line Items]
Gross	$ 10,352	$ 5,240
Accumulated Amortization	(6,189)	(2,830)
Total	$ 4,163	$ 2,410
Weighted average remaining amortization period in years (in years)	1 year	2 years