Document and Entity Information - USD ($)	12 Months Ended
	Mar. 31, 2016	May. 17, 2016	Sep. 30, 2015
Document and Entity Information
Entity Registrant Name	AMERICAN SCIENCE & ENGINEERING, INC.
Entity Central Index Key	0000005768
Document Type	10-K
Document Period End Date	Mar. 31, 2016
Amendment Flag	false
Current Fiscal Year End Date	--03-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Public Float			$ 250,549,000
Entity Common Stock, Shares Outstanding		7,131,731
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	FY