Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Finite Lived And Indefinite Lived Intangible Assets By Major Class [Line Items]
Useful life - acquired	3 years
Amortization expenses	$ 51,495,000	$ 64,225,000	$ 61,667,000
Trade names
Finite Lived And Indefinite Lived Intangible Assets By Major Class [Line Items]
Impairment of intangible assets	0	0	0
Student relationships
Finite Lived And Indefinite Lived Intangible Assets By Major Class [Line Items]
Amortization expenses	$ 44,300,000	$ 57,300,000	$ 55,300,000