Operating Leases - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) campus	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
HCN Segment
Property, Plant and Equipment [Line Items]
Number of campuses | campus	5
Rent expense	$ 2,814	$ 2,729	$ 2,528
APEI Segment
Property, Plant and Equipment [Line Items]
Rent expense	$ 559	$ 677	$ 584