| Submission | Jan. 21, 2025 |
| Submission [Line Items] | |
| Central Index Key | 0000755001 |
| Registrant Name | Unitil Corporation |
| Form Type | S-8 |
| Submission Type | S-8 |
| Fee Exhibit Type | EX-FILING FEES |
| Offerings - Offering: 1 | Jan. 21, 2025 USD ($) shares |
| Offering: | |
| Fee Previously Paid | false |
| Other Rule | true |
| Security Type | Equity |
| Security Class Title | Common Stock |
| Amount Registered | shares | 350,000 |
| Proposed Maximum Offering Price per Unit | 54.31 |
| Maximum Aggregate Offering Price | $ 19,008,500 |
| Fee Rate | 0.01531% |
| Amount of Registration Fee | $ 2,910.2 |
| Offering Note | (1) Pursuant to Rule 416(a) under the Securities Act of 1933, as amended (the “ Securities Act (2) Calculated pursuant to Rule 457(c) of the Securities Act, based on the average high and low prices reported on the New York Stock Exchange under the symbol “UTL” on January 16, 2025, which is within five (5) business days of the filing hereof. |
| Fees Summary | Jan. 21, 2025 USD ($) |
| Fees Summary [Line Items] | |
| Total Offering | $ 19,008,500 |
| Previously Paid Amount | 0 |
| Total Fee Amount | 2,910.2 |
| Total Offset Amount | 0 |
| Net Fee | $ 2,910.2 |
