Document and Entity Information (USD $) Share data in Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Aug. 07, 2013
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 Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float	$ 80,922,178
Entity Common Stock, Shares Outstanding		5,953,369
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q2
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2013