| Cover | Oct. 27, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Oct. 27, 2021 |
| Entity File Number | 0-33203 |
| Entity Registrant Name | Landmark Bancorp, Inc. |
| Entity Central Index Key | 0001141688 |
| Entity Tax Identification Number | 43-1930755 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 701 Poyntz Avenue |
| Entity Address, City or Town | Manhattan |
| Entity Address, State or Province | KS |
| Entity Address, Postal Zip Code | 66502 |
| City Area Code | 785 |
| Local Phone Number | 565-2000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, par value $0.01 per share |
| Trading Symbol | LARK |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
