Document and Entity Information	6 Months Ended
	Mar. 31, 2013	Apr. 30, 2013
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2013
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q2
Trading Symbol	APFC
Entity Registrant Name	AMERICAN PACIFIC CORP
Entity Central Index Key	0000350832
Current Fiscal Year End Date	--09-30
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		7,866,573