Document and Entity Information In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Nov. 08, 2012
Document and Entity Information [Abstract]
Entity Registrant Name	FIRST MID ILLINOIS BANCSHARES INC
Entity Central Index Key	0000700565
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		6,032,682
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q3
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2012