Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Revenues	$ 1,131,686	$ 1,027,653	$ 997,137
U.S. Higher Education
Disaggregation of Revenue [Line Items]
Revenues	829,270	966,579	963,052
U.S. Higher Education | Tuition, net of discounts, grants and scholarships
Disaggregation of Revenue [Line Items]
Revenues	795,266	928,476	923,534
U.S. Higher Education | Other
Disaggregation of Revenue [Line Items]
Revenues	34,004	38,103	39,518
Australia / New Zealand
Disaggregation of Revenue [Line Items]
Revenues	250,124	23,381	0
Australia / New Zealand | Tuition, net of discounts, grants and scholarships
Disaggregation of Revenue [Line Items]
Revenues	245,791	22,431	0
Australia / New Zealand | Other
Disaggregation of Revenue [Line Items]
Revenues	4,333	950	0
Education Technology Services
Disaggregation of Revenue [Line Items]
Revenues	$ 52,292	$ 37,693	$ 34,085