| Cover | Mar. 30, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Mar. 30, 2021 |
| Entity File Number | 0-20167 |
| Entity Registrant Name | MACKINAC FINANCIAL CORP /MI/ |
| Entity Central Index Key | 0000036506 |
| Entity Tax Identification Number | 38-2062816 |
| Entity Incorporation, State or Country Code | MI |
| 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 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock |
| Trading Symbol | MFNC |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
