Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation of Revenue [Line Items]
Revenues	$ 299,173	$ 255,831	$ 589,509	$ 521,133
U.S. Higher Education Segment
Disaggregation of Revenue [Line Items]
Revenues	212,207	247,350	438,754	502,863
U.S. Higher Education Segment | Tuition, net of discounts, grants and scholarships
Disaggregation of Revenue [Line Items]
Revenues	203,433	237,696	420,910	483,016
U.S. Higher Education Segment | Other
Disaggregation of Revenue [Line Items]
Revenues	8,774	9,654	17,844	19,847
Australia/New Zealand Segment
Disaggregation of Revenue [Line Items]
Revenues	74,060	0	125,325	0
Australia/New Zealand Segment | Tuition, net of discounts, grants and scholarships
Disaggregation of Revenue [Line Items]
Revenues	72,340	0	122,562	0
Australia/New Zealand Segment | Other
Disaggregation of Revenue [Line Items]
Revenues	1,720	0	2,763	0
Alternative Learning
Disaggregation of Revenue [Line Items]
Revenues	$ 12,906	$ 8,481	$ 25,430	$ 18,270