| Document and Entity Information Document | Oct. 24, 2019 |
| Document and Entity Information [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Oct. 24, 2019 |
| Entity Registrant Name | MidWestOne Financial Group, Inc. |
| Entity File Number | 001-35968 |
| Entity Incorporation, State or Country Code | IA |
| Entity Tax Identification Number | 42-1206172 |
| Entity Address, Address Line One | 102 South Clinton Street |
| Entity Address, City or Town | Iowa City |
| Entity Address, State or Province | IA |
| Entity Address, Postal Zip Code | 52240 |
| City Area Code | 319 |
| Local Phone Number | 356-5800 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common stock, $1.00 par value |
| Trading Symbol | MOFG |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Amendment Flag | false |
| Entity Central Index Key | 0001412665 |
