Document and Entity Information (USD $)	12 Months Ended
	Sep. 30, 2013	Nov. 29, 2013	Mar. 28, 2013
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Sep. 30, 2013
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	FY
Trading Symbol	APFC
Entity Registrant Name	AMERICAN PACIFIC CORP
Entity Central Index Key	0000350832
Current Fiscal Year End Date	--09-30
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		7,954,000
Entity Public Float			$ 172,400,000