Document and Entity Information - USD ($)	3 Months Ended
	Mar. 31, 2019	May 07, 2019	Jun. 30, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	FIRST MID BANCSHARES, INC.
Entity Central Index Key	0000700565
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Current Reporting Status	Yes
Entity Public Float			$ 513,588,874
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Document Type	10-Q
Amendment Flag	false
Entity Common Stock, Shares Outstanding		16,677,128
Entity Small Business	false
Entity Emerging Growth Company	false
Document Period End Date	Mar. 31, 2019