Document and Entity Information	3 Months Ended
	Mar. 31, 2015	May 07, 2015
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Trading Symbol	APEI
Entity Registrant Name	AMERICAN PUBLIC EDUCATION INC
Entity Central Index Key	0001201792
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		17,146,418