Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Mar. 31, 2022	Jun. 30, 2022	Dec. 31, 2021
Amortizable Intangible Assets
Gross Carrying Amount		$ 722,713	$ 696,594
Accumulated Amortization		(335,827)	(286,071)
Net Carrying Amount		386,886	410,523
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Indefinite-lived intangible assets		255,000	255,000
Accumulated Impairments*		(30,000)	0
Net Carrying Amount		225,000	255,000
Impairment of intangible assets, indefinite-lived (excluding goodwill)	$ 30,000
Trade names
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Indefinite-lived intangible assets		255,000	255,000
Accumulated Impairments*		(30,000)	0
Net Carrying Amount		225,000	255,000
Capitalized technology
Amortizable Intangible Assets
Gross Carrying Amount		209,976	199,766
Accumulated Amortization		(117,948)	(112,357)
Net Carrying Amount		$ 92,028	87,409
Capitalized technology | Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated Average Useful Life (in years)		3 years
Capitalized technology | Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated Average Useful Life (in years)		5 years
Capitalized content development
Amortizable Intangible Assets
Gross Carrying Amount		$ 258,285	243,687
Accumulated Amortization		(152,311)	(125,599)
Net Carrying Amount		$ 105,974	118,088
Capitalized content development | Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated Average Useful Life (in years)		4 years
Capitalized content development | Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated Average Useful Life (in years)		5 years
University client relationships
Amortizable Intangible Assets
Gross Carrying Amount		$ 211,171	211,680
Accumulated Amortization		(45,285)	(34,995)
Net Carrying Amount		$ 165,886	176,685
University client relationships | Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated Average Useful Life (in years)		9 years
University client relationships | Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated Average Useful Life (in years)		10 years
Enterprise client relationships
Finite-Lived Intangible Assets [Line Items]
Estimated Average Useful Life (in years)		10 years
Amortizable Intangible Assets
Gross Carrying Amount		$ 14,300	14,300
Accumulated Amortization		(1,073)	(179)
Net Carrying Amount		13,227	14,121
Trade names and domain names
Amortizable Intangible Assets
Gross Carrying Amount		28,981	27,161
Accumulated Amortization		(19,210)	(12,941)
Net Carrying Amount		$ 9,771	$ 14,220
Trade names and domain names | Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated Average Useful Life (in years)		5 years
Trade names and domain names | Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated Average Useful Life (in years)		10 years