| Cover Page | Jul. 30, 2021 | May 04, 2021 |
| Cover [Abstract] | ||
| Document Type | 8-K | |
| Document Period End Date | Jul. 30, 2021 | |
| 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 |
