Business Combinations - Narrative (Details) student in Thousands, $ in Thousands		12 Months Ended
	Nov. 03, 2020 USD ($) industry student	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Business Acquisition [Line Items]
Goodwill		$ 1,285,864	$ 1,318,526	$ 732,075
Measurement period adjustment, goodwill		262	$ 0
Torrens University and Related Assets in Australia and New Zealand (ANZ)
Business Acquisition [Line Items]
Number of students | student	19
Number of industries | industry	5
Purchase price paid in cash at closing	$ 658,400
Value of business acquisition agreement	642,700
Purchase price adjustment	15,700
Net cash increase at closing	11,000
Working capital increase at closing	4,700
Goodwill	546,315
Transaction costs	$ 8,100
Measurement period adjustment, property and equipment		300
Measurement period adjustment, goodwill		$ 300