Document and Entity Information - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Mar. 10, 2021	Jun. 30, 2020
Document and Entity Information
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Transition Report	false
Entity File Number	0-20167
Entity Registrant Name	MACKINAC FINANCIAL CORP /MI/
Entity Incorporation, State or Country Code	MI
Entity Tax Identification Number	38-2062816
Entity Address, Address Line One	130 South Cedar Street
Entity Address, City or Town	Manistique
Entity Address, State or Province	MI
Entity Address, Postal Zip Code	49854
City Area Code	888
Local Phone Number	343-8147
Title of 12(b) Security	Common Stock, no par value
Trading Symbol	MFNC
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		10,550,393
ICFR Auditor Attestation Flag	true
Entity Public Float			$ 109,233
Entity Central Index Key	0000036506
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false