| Pay vs Performance Disclosure | 12 Months Ended |
| Dec. 31, 2022 USD ($) | Dec. 31, 2021 USD ($) | Dec. 31, 2020 USD ($) |
| Pay vs Performance Disclosure [Table] | | | |
| Pay vs Performance [Table Text Block] | (a) (b) (c) (d) (e) (f) (g) (h) (i) Value of Initial Fixed $100 Investment Based on Company Selected Measure (CSM): Year Summary Compensation Table Total for Principal Executive Officer (PEO) (1) Compensation Actually Paid (CAP) to PEO (2) Average Summary Compensation Table Total for Non-PEO NEOs (3) Average Compensation Actually Paid to Non-PEO NEOs (4) Company Total Shareholder Return (TSR) (5) Peer Group TSR (6) Net Income (in Millions) (7) Return on Average Assets (8) 2022 $ 1,328,910 $ 991,735 $ 672,157 $ 534,656 87.32 112.01 $ 93.41 1.24 % 2021 1,402,359 1,697,391 660,875 793,996 119.35 127.67 87.09 1.34 % 2020 1,281,359 1,170,072 597,220 584,447 86.18 90.39 68.50 1.22 % | | |
| Named Executive Officers, Footnote [Text Block] | The dollar amounts reported in column (b) are the amounts of total compensation reported for Mr. Dwight, our Chief Executive Officer, for each corresponding year in the “Total” column of the Summary Compensation Table (“SCT”). See “Executive Compensation – Executive Compensation Tables – Summary Compensation Table for 2022.”The dollar amounts reported in column (d) represent the average of the amounts reported for Horizon’s named executive officers (NEOs) as a group (excluding Mr. Dwight) in the “Total” column of the Summary Compensation Table in each applicable year. The names of each of the NEOs (excluding Mr. Dwight) included for purposes of calculating the average amounts in each applicable year are as follows: (i) for 2022, Mark E. Secor, Thomas M. Prame, Kathie A. DeRuiter, and Lynn M. Kerber (ii) for 2021, James D. Neff, Mark E. Secor, Dennis J. Kuhn, and Kathie A. DeRuiter; and (iii) for 2020, James D. Neff, Mark E. Secor, Dennis J. Kuhn, and Kathie A. DeRuiter. | | |
| Peer Group Issuers, Footnote [Text Block] | Peer Group TSR the SNL Micro Cap Bank Index is illustrated.Total Shareholder Return of Horizon and Total Shareholder Return of Peer GroupThe Company’s TSR over the three year period presented in the table is aligned with compensation actually paid when comparing the TSR of the peer group presented over the three years presented in the table. The Company’s TSR during the three years presented in the table, representing the Company’s financial performance, industry performance and market conditions as compared to the companies comprising the peer group were directionally consistent. For more information regarding the Company’s performance and the companies that the Compensation Committee considers when determining compensation, refer to “Compensation Discussion and Analysis.” | | |
| PEO Total Compensation Amount | $ 1,328,910 | $ 1,402,359 | $ 1,281,359 |
| PEO Actually Paid Compensation Amount | $ 991,735 | 1,697,391 | 1,170,072 |
| Adjustment To PEO Compensation, Footnote [Text Block] | Compensation Actually Paid to PEO Year Salary Stock Awards Non–Equity Incentive Plan Compensation All Other Compensation SCT Total Deductions from SCT Total Additions to SCT Total CAP 2022 $ 635,000 $ 419,969 $ 190,500 $ 83,441 $ 1,328,910 $ (419,969) $ 82,794 $ 991,735 2021 605,000 284,980 438,625 73,754 1,402,359 (284,980) 580,012 1,697,391 2020 585,000 260,000 365,625 70,734 1,281,359 (260,000) 148,713 1,170,072 (A) The dollar amounts in the “Salary” column are the amounts reported for Mr. Dwight for each corresponding year in the “Salary” column of the Summary Compensation Table. (B) The dollar amounts in the “Stock Awards” column are the amounts reported for Mr. Dwight for each corresponding year in the “Stock Awards” column of the SCT. (C) The dollar amounts in the “Non-Equity Incentive Plan Compensation” column are the amounts reported for Mr. Dwight for each corresponding year in the “Non-Equity Incentive Plan Compensation” column of the SCT. (D) The dollar amounts in the “All Other Compensation” column are the amounts reported for Mr. Dwight for each corresponding year in the “All Other Compensation” column of the SCT. (E) The dollar amounts in the “SCT Total” column are the amounts reported for Mr. Dwight for each corresponding year in the “Total” column of the SCT. (F) The dollar amounts in the “Deductions from SCT Total” column are the total of the amounts reported for Mr. Dwight in the “Stock Awards” and “Option Awards” columns in the SCT for the applicable year. (G) The dollar amount in the “Additions to SCT Total” column reflects the addition (or subtraction, as applicable) of the following equity award adjustments for Mr. Dwight for the applicable year: (i) the year-end fair value of any equity awards granted in the applicable year that are outstanding and unvested as of the end of the year; (ii) the amount of change as of the end of the applicable year (from the end of the prior fiscal year) in fair value of any awards granted in prior years that are outstanding and unvested as of the end of the applicable year; (iii) for awards that are granted and vest in same applicable year, the fair value as of the vesting date; (iv) for awards granted in prior years that vest in the applicable year, the amount equal to the change as of the vesting date (from the end of the prior fiscal year) in fair value; (v) for awards granted in prior years that are determined to fail to meet the applicable vesting conditions during the applicable year, a deduction for the amount equal to the fair value at the end of the prior fiscal year; and (vi) the dollar value of any dividends or other earnings paid on stock or option awards in the applicable year prior to the vesting date that are not otherwise reflected in the fair value of such award or included in any other component of total compensation for the applicable year. | | |
| Non-PEO NEO Average Total Compensation Amount | $ 672,157 | 660,875 | 597,220 |
| Non-PEO NEO Average Compensation Actually Paid Amount | $ 534,656 | 793,996 | 584,447 |
| Adjustment to Non-PEO NEO Compensation Footnote [Text Block] | Compensation Actually Paid to Non–PEO Year Salary Stock Awards Non–Equity Incentive Plan Compensation All Other Compensation SCT Total Deductions from SCT Total Additions to SCT Total CAP 2022 $ 283,549 $ 253,466 $ 92,942 $ 42,200 $ 672,157 $ (253,466) $ 115,965 $ 534,656 2021 322,072 128,829 154,413 55,561 660,875 (128,829) 261,950 793,996 2020 310,733 124,293 104,143 58,051 597,220 (124,293) 111,520 584,447 (5) TSR for Horizon Bancorp, Inc. cumulative total TSR returns on common share from S&P Global Market Intelligence, respectively for each period. (6) Peer Group TSR the SNL Micro Cap Bank Index is illustrated. (7) The dollar amounts reported represent the amount of net income reflected in the Company’s audited financial statements for the applicable year. (8) The percentages reported represent the amount of net income reflected in the Company’s audited financial statements divided by the reported average assets for the applicable year. | | |
| Compensation Actually Paid vs. Total Shareholder Return [Text Block] | Compensation Actually Paid and Total Shareholder Return The amount of compensation actually paid to Mr. Dwight and the average amount of compensation actually paid to the Company’s NEOs as a group (excluding Mr. Dwight) are aligned with the Company’s cumulative TSR over the three years presented in the table. The alignment of compensation actually paid with the Company’s cumulative TSR over the period presented is because a significant portion of the compensation actually paid to Mr. Dwight and to the other NEOs is comprised of equity awards. As described in more detail in the section “ Compensation Discussion and Analysis | | |
| Compensation Actually Paid vs. Net Income [Text Block] | Compensation Actually Paid and Net Income The amount of compensation actually paid to Mr. Dwight and the average amount of compensation actually paid to the Company’s NEOs as a group (excluding Mr. Dwight) are generally aligned with the Company’s net income between 2020 and 2021 as presented in the table, but net income increased between 2021 and 2022 while the amount of compensation actually paid to Mr. Dwight and the average amount of compensation actually paid to the Company’s NEOs as a group (excluding Mr. Dwight) decreased. This was primarily the result of the Company’s stock price decreasing during 2022, | | |
| Compensation Actually Paid vs. Company Selected Measure [Text Block] | Compensation Actually Paid and Return on Average Assets The amount of compensation actually paid to Mr. Dwight and the average amount of compensation actually paid to the Company’s NEOs as a group (excluding Mr. Dwight) are generally aligned with the Company’s net income between 2020 and 2021 as presented in the table, but net income increased between 2021 and 2022 while the amount of compensation actually paid to Mr. Dwight and the average amount of compensation actually paid to the Company’s NEOs as a group (excluding Mr. Dwight) decreased. This was primarily the result of the Company’s stock price decreasing during 2022, | | |
| Tabular List [Table Text Block] | • Revenue • Return on Average Assets • Relative TSR (the Company’s TSR as compared to a peer group established by the Compensation Committee) | | |
| Total Shareholder Return Amount | $ 87.32 | 119.35 | 86.18 |
| Peer Group Total Shareholder Return Amount | 112.01 | 127.67 | 90.39 |
| Net Income (Loss) | $ 93,410,000 | $ 87,090,000 | $ 68,500,000 |
| Company Selected Measure Amount | 0.0124 | 0.0134 | 0.0122 |
| PEO Name | Mr. Dwight | | |
| Additional 402(v) Disclosure [Text Block] | The dollar amounts reported in column (c) represent the amount of “compensation actually paid” to Mr. Dwight, as computed in accordance with Item 402(v) of Regulation S-K. The dollar amounts do not reflect the actual amount of compensation earned by or paid to Mr. Dwight during the applicable year. In accordance with the requirements of Item 402(v) of Regulation S-K, the following adjustments were made to Mr. Dwight’s total compensation for each year to determine the compensation actually paid: Compensation Actually Paid to PEO Year Salary Stock Awards Non–Equity Incentive Plan Compensation All Other Compensation SCT Total Deductions from SCT Total Additions to SCT Total CAP 2022 $ 635,000 $ 419,969 $ 190,500 $ 83,441 $ 1,328,910 $ (419,969) $ 82,794 $ 991,735 2021 605,000 284,980 438,625 73,754 1,402,359 (284,980) 580,012 1,697,391 2020 585,000 260,000 365,625 70,734 1,281,359 (260,000) 148,713 1,170,072 (A) The dollar amounts in the “Salary” column are the amounts reported for Mr. Dwight for each corresponding year in the “Salary” column of the Summary Compensation Table. (B) The dollar amounts in the “Stock Awards” column are the amounts reported for Mr. Dwight for each corresponding year in the “Stock Awards” column of the SCT. (C) The dollar amounts in the “Non-Equity Incentive Plan Compensation” column are the amounts reported for Mr. Dwight for each corresponding year in the “Non-Equity Incentive Plan Compensation” column of the SCT. (D) The dollar amounts in the “All Other Compensation” column are the amounts reported for Mr. Dwight for each corresponding year in the “All Other Compensation” column of the SCT. (E) The dollar amounts in the “SCT Total” column are the amounts reported for Mr. Dwight for each corresponding year in the “Total” column of the SCT. (F) The dollar amounts in the “Deductions from SCT Total” column are the total of the amounts reported for Mr. Dwight in the “Stock Awards” and “Option Awards” columns in the SCT for the applicable year. (G) The dollar amount in the “Additions to SCT Total” column reflects the addition (or subtraction, as applicable) of the following equity award adjustments for Mr. Dwight for the applicable year: (i) the year-end fair value of any equity awards granted in the applicable year that are outstanding and unvested as of the end of the year; (ii) the amount of change as of the end of the applicable year (from the end of the prior fiscal year) in fair value of any awards granted in prior years that are outstanding and unvested as of the end of the applicable year; (iii) for awards that are granted and vest in same applicable year, the fair value as of the vesting date; (iv) for awards granted in prior years that vest in the applicable year, the amount equal to the change as of the vesting date (from the end of the prior fiscal year) in fair value; (v) for awards granted in prior years that are determined to fail to meet the applicable vesting conditions during the applicable year, a deduction for the amount equal to the fair value at the end of the prior fiscal year; and (vi) the dollar value of any dividends or other earnings paid on stock or option awards in the applicable year prior to the vesting date that are not otherwise reflected in the fair value of such award or included in any other component of total compensation for the applicable year. Compensation Actually Paid to Non–PEO Year Salary Stock Awards Non–Equity Incentive Plan Compensation All Other Compensation SCT Total Deductions from SCT Total Additions to SCT Total CAP 2022 $ 283,549 $ 253,466 $ 92,942 $ 42,200 $ 672,157 $ (253,466) $ 115,965 $ 534,656 2021 322,072 128,829 154,413 55,561 660,875 (128,829) 261,950 793,996 2020 310,733 124,293 104,143 58,051 597,220 (124,293) 111,520 584,447 (5) TSR for Horizon Bancorp, Inc. cumulative total TSR returns on common share from S&P Global Market Intelligence, respectively for each period. (6) Peer Group TSR the SNL Micro Cap Bank Index is illustrated. (7) The dollar amounts reported represent the amount of net income reflected in the Company’s audited financial statements for the applicable year. (8) The percentages reported represent the amount of net income reflected in the Company’s audited financial statements divided by the reported average assets for the applicable year. Analysis of the Information Presented in the Pay versus Performance Table In accordance with Item 402(v) of Regulation S-K, the Company is providing the following descriptions of the relationships between information presented in the Pay Versus Performance table. | | |
| PEO Salary | $ 635,000 | $ 605,000 | $ 585,000 |
| PEO Equity Incentive Plan Compensation | 419,969 | 284,980 | 260,000 |
| PEO Non-Equity Incentive Compensation | 190,500 | 438,625 | 365,625 |
| PEO Other Compensation | 83,441 | 73,754 | 70,734 |
| Non-PEO NEO Salary | 283,549 | 322,072 | 310,733 |
| Non-PEO NEO Equity Incentive Plan Compensation | 253,466 | 128,829 | 124,293 |
| Non-PEO NEO Non-Equity Incentive Compensation | 92,942 | 154,413 | 104,143 |
| Non-PEO NEO Other Compensation | $ 42,200 | 55,561 | 58,051 |
| Measure [Axis]: 1 | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Measure Name | •Revenue | | |
| Measure [Axis]: 2 | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Measure Name | •Return on Average Assets | | |
| Measure [Axis]: 3 | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Measure Name | •Relative TSR (the Company’s TSR as compared to a peer group established by the Compensation Committee) | | |
| PEO [Member] | Deductions [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | $ (419,969) | (284,980) | (260,000) |
| PEO [Member] | Additions [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | 82,794 | 580,012 | 148,713 |
| Non-PEO NEO [Member] | Deductions [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | (253,466) | (128,829) | (124,293) |
| Non-PEO NEO [Member] | Additions [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | $ 115,965 | $ 261,950 | $ 111,520 |
