CONDENSED BALANCE SHEETS (Parenthetical) - $ / shares |
Jun. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Kirby stockholders' equity: | ||
| Common stock, par value per share (in dollars per share) | $ 0.1 | $ 0.1 |
| Common stock, shares authorized (in shares) | 120,000,000 | 120,000,000 |
| Common stock, shares issued (in shares) | 65,500,000 | 65,500,000 |
| Treasury stock, shares | 12,400,000 | 11,700,000 |
| X | ||||||||||
- Definition Face amount or stated value per share of common stock. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition The maximum number of common shares permitted to be issued by an entity's charter and bylaws. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Number of previously issued common shares repurchased by the issuing entity and held in treasury. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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