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Incentive Plans - Narrative (Details) | 1 Months Ended | 3 Months Ended |  |
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Feb. 29, 2024 peer_company $ / shares | Mar. 31, 2025 USD ($) $ / shares shares | Mar. 31, 2024 USD ($) | Dec. 31, 2024 $ / shares shares | May 04, 2023 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Share-based compensation | $ |  | $ 5,900,000 | $ 5,600,000 |  |
Total income tax benefits realized from tax deductions related to stock option exercises under share-based payment arrangements | $ |  | $ 0 | $ 500,000 |  |
MUSA 2013 Plan |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Number of shares authorized for incentive plan (no more than) (in shares) |  | 5,500,000 |  |  |
Number of shares per employee (no more than) (in shares) |  | 1,000,000 |  |  |
Maximum amount payable | $ |  | $ 5,000,000 |  |  |
MUSA 2023 Plan |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Number of shares authorized for incentive plan (no more than) (in shares) |  |  |  |  | 1,725,000
Award expiration period (in years) |  | 7 years |  |  |
Shares granted, fair value (in dollars per share) | $ / shares |  | $ 154.07 |  |  |
MUSA 2023 Plan | RSUs |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Award vesting period (in years) |  | 3 years |  |  |
MUSA 2023 Plan | RSUs | Non-employee directors |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Award vesting period (in years) |  | 1 year |  |  |
Granted (in shares) |  | 12,674 |  |  |
Outstanding (in shares) |  | 72,970 |  | 98,214 |
Weighted average grant date fair value (in dollars per share) | $ / shares |  | $ 362.23 |  | $ 285.60 |
Restricted stock units issued, weighted average grant date fair value (in dollars per share) | $ / shares |  | $ 492.34 |  |  |
MUSA 2023 Plan | RSUs | In 2023 | Non-employee directors |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Award vesting period (in years) |  | 1 year |  |  |
MUSA 2023 Plan | DSUs | Non-employee directors |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Share of common stock right |  | 1 |  |  |
Granted (in shares) |  | 192 |  |  |
Share-based compensation | $ |  | $ 100,000 |  |  |
Outstanding (in shares) |  | 1,931 |  |  |
Weighted average grant date fair value (in dollars per share) | $ / shares |  | $ 399.31 |  |  |
MUSA 2023 Plan | Return On Average Capital Employed Performance Units |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Award vesting period (in years) | 3 years |  |  |  |
MUSA 2023 Plan | Total Shareholder Return Performance Units |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Award vesting period (in years) | 3 years |  |  |  |
Number of companies in total shareholder return peer comparison group | peer_company | 17 |  |  |  |
MUSA 2023 Plan | PSUs | TSR |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Restricted stock units issued, weighted average grant date fair value (in dollars per share) | $ / shares | $ 674.28 |  |  |  |
MUSA 2023 Plan | PSUs | ROACE |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Restricted stock units issued, weighted average grant date fair value (in dollars per share) | $ / shares | $ 492.22 |  |  |  |
2013 Directors Plan | RSUs | Non-employee directors |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Granted (in shares) |  | 2 |  |  |
Outstanding (in shares) |  | 2,264 |  | 9,436 |
Weighted average grant date fair value (in dollars per share) | $ / shares |  | $ 261.51 |  | $ 196.38 |
Restricted stock units issued, weighted average grant date fair value (in dollars per share) | $ / shares |  | $ 457.52 |  |  |
2013 Directors Plan | RSUs | In 2023 | Non-employee directors |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Award vesting period (in years) |  | 1 year |  |  |
2013 Directors Plan | RSUs | Prior to 2023 | Non-employee directors |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Award vesting period (in years) |  | 3 years |  |  |
2013 Directors Plan | DSUs | Non-employee directors |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Share of common stock right |  | 1 |  |  |
Outstanding (in shares) |  | 425 |  |  |
Weighted average grant date fair value (in dollars per share) | $ / shares |  | $ 258.35 |  |  |

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