Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Total Revenue	$ 154,000	$ 98,248	$ 78,014	$ 88,541	$ 85,909	$ 79,133	$ 82,127	$ 74,616	$ 418,803	$ 321,785	$ 286,270
Instructional services, net of grants and scholarships
Disaggregation of Revenue [Line Items]
Total Revenue									394,590	313,930	280,240
Graduation fees
Disaggregation of Revenue [Line Items]
Total Revenue									1,309	1,336	1,138
Textbook and other course materials
Disaggregation of Revenue [Line Items]
Total Revenue									20,156	5,197	3,650
Other fees
Disaggregation of Revenue [Line Items]
Total Revenue									2,748	1,322	1,242
Operating Segments | APUS
Disaggregation of Revenue [Line Items]
Total Revenue									283,700	285,938	257,050
Operating Segments | APUS | Instructional services, net of grants and scholarships
Disaggregation of Revenue [Line Items]
Total Revenue									281,689	283,827	255,130
Operating Segments | APUS | Graduation fees
Disaggregation of Revenue [Line Items]
Total Revenue									1,309	1,336	1,138
Operating Segments | APUS | Textbook and other course materials
Disaggregation of Revenue [Line Items]
Total Revenue									0	0	0
Operating Segments | APUS | Other fees
Disaggregation of Revenue [Line Items]
Total Revenue									702	775	782
Operating Segments | RU
Disaggregation of Revenue [Line Items]
Total Revenue									89,483	0	0
Operating Segments | RU | Instructional services, net of grants and scholarships
Disaggregation of Revenue [Line Items]
Total Revenue									74,515	0	0
Operating Segments | RU | Graduation fees
Disaggregation of Revenue [Line Items]
Total Revenue									0	0	0
Operating Segments | RU | Textbook and other course materials
Disaggregation of Revenue [Line Items]
Total Revenue									13,461	0	0
Operating Segments | RU | Other fees
Disaggregation of Revenue [Line Items]
Total Revenue									1,507	0	0
Operating Segments | HCN
Disaggregation of Revenue [Line Items]
Total Revenue									45,803	36,091	29,479
Operating Segments | HCN | Instructional services, net of grants and scholarships
Disaggregation of Revenue [Line Items]
Total Revenue									38,569	30,346	25,369
Operating Segments | HCN | Graduation fees
Disaggregation of Revenue [Line Items]
Total Revenue									0	0	0
Operating Segments | HCN | Textbook and other course materials
Disaggregation of Revenue [Line Items]
Total Revenue									6,695	5,197	3,650
Operating Segments | HCN | Other fees
Disaggregation of Revenue [Line Items]
Total Revenue									539	548	460
Intersegment
Disaggregation of Revenue [Line Items]
Total Revenue									(183)	(244)	(259)
Intersegment | Instructional services, net of grants and scholarships
Disaggregation of Revenue [Line Items]
Total Revenue									(183)	(243)	(259)
Intersegment | Graduation fees
Disaggregation of Revenue [Line Items]
Total Revenue									0	0	0
Intersegment | Textbook and other course materials
Disaggregation of Revenue [Line Items]
Total Revenue									0	0	0
Intersegment | Other fees
Disaggregation of Revenue [Line Items]
Total Revenue									$ 0	$ (1)	$ 0