Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2011	Feb. 13, 2012	Jul. 03, 2011
Document And Entity Information
Entity Registrant Name	FEI CO
Trading Symbol	FEIC
Entity Central Index Key	0000914329
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2011
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	Yes
Entity Common Stock, Shares Outstanding		37,877,286
Public Float, Share Price			$ 38.86
Entity Public Float			$ 1,518,272,557