Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Total Revenue	$ 79,133	$ 67,888	$ 235,876	$ 211,889
Instructional services, net of grants and scholarships
Disaggregation of Revenue [Line Items]
Total Revenue	76,969	66,365	230,227	207,493
Graduation fees
Disaggregation of Revenue [Line Items]
Total Revenue	400	352	1,001	936
Textbook and other course materials
Disaggregation of Revenue [Line Items]
Total Revenue	1,411	854	3,634	2,515
Other fees
Disaggregation of Revenue [Line Items]
Total Revenue	353	317	1,014	945
Intersegment
Disaggregation of Revenue [Line Items]
Total Revenue	(18)	(25)	(57)	(81)
Intersegment | Instructional services, net of grants and scholarships
Disaggregation of Revenue [Line Items]
Total Revenue	(18)	(25)	(57)	(81)
Intersegment | Graduation fees
Disaggregation of Revenue [Line Items]
Total Revenue	0	0	0	0
Intersegment | Textbook and other course materials
Disaggregation of Revenue [Line Items]
Total Revenue	0	0	0	0
Intersegment | Other fees
Disaggregation of Revenue [Line Items]
Total Revenue	0	0	0	0
APEI | Operating Segments
Disaggregation of Revenue [Line Items]
Total Revenue	69,610	61,217	210,251	190,386
APEI | Operating Segments | Instructional services, net of grants and scholarships
Disaggregation of Revenue [Line Items]
Total Revenue	69,010	60,668	208,648	188,839
APEI | Operating Segments | Graduation fees
Disaggregation of Revenue [Line Items]
Total Revenue	400	352	1,001	936
APEI | Operating Segments | Textbook and other course materials
Disaggregation of Revenue [Line Items]
Total Revenue	0	0	0	0
APEI | Operating Segments | Other fees
Disaggregation of Revenue [Line Items]
Total Revenue	200	197	602	611
HCN | Operating Segments
Disaggregation of Revenue [Line Items]
Total Revenue	9,541	6,696	25,682	21,584
HCN | Operating Segments | Instructional services, net of grants and scholarships
Disaggregation of Revenue [Line Items]
Total Revenue	7,977	5,722	21,636	18,735
HCN | Operating Segments | Graduation fees
Disaggregation of Revenue [Line Items]
Total Revenue	0	0	0	0
HCN | Operating Segments | Textbook and other course materials
Disaggregation of Revenue [Line Items]
Total Revenue	1,411	854	3,634	2,515
HCN | Operating Segments | Other fees
Disaggregation of Revenue [Line Items]
Total Revenue	$ 153	$ 120	$ 412	$ 334