| Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] |
| | | Three Months Ended June 30, | | | Six Months Ended June 30, | |
| | | 2026 | | | 2025 | | | 2026 | | | 2025 | |
| Numerator | | | | | | | | | | | | | | | | |
| Net income attributable to Generac Holdings Inc. | | $ | 143,244 | | | $ | 74,016 | | | $ | 216,497 | | | $ | 117,856 | |
| Net income attributable to common shareholders | | $ | 143,244 | | | $ | 74,016 | | | $ | 216,497 | | | $ | 117,856 | |
| | | | | | | | | | | | | | | | | |
| Denominator | | | | | | | | | | | | | | | | |
| Weighted average shares, basic | | | 58,822,634 | | | | 58,496,998 | | | | 58,615,919 | | | | 58,771,818 | |
| Dilutive effect of stock compensation awards (1) | | | 812,813 | | | | 520,825 | | | | 820,460 | | | | 614,089 | |
| Weighted average shares, diluted | | | 59,635,447 | | | | 59,017,823 | | | | 59,436,379 | | | | 59,385,907 | |
| | | | | | | | | | | | | | | | | |
| Net income attributable to common shareholders per share | | | | | | | | | | | | | | | | |
| Basic | | $ | 2.44 | | | $ | 1.27 | | | $ | 3.69 | | | $ | 2.01 | |
| Diluted | | $ | 2.40 | | | $ | 1.25 | | | $ | 3.64 | | | $ | 1.98 | |
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