Acquisitions - Pro Forma Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
Mar. 30, 2024	Apr. 01, 2023
Pro Forma Information
Increase (decrease) in cost of revenue	$ 138,013	$ 127,712
Increase (decrease) in selling, general, and administrative expenses	70,305	58,562
2024 Acquisitions
Business Acquisition [Line Items]
Revenue	251,640	257,391
Net Income Attributable to Kadant	$ 27,310	$ 24,824
Earnings per Share Attributable to Kadant
Basic (in dollars per share)	$ 2.33	$ 2.13
Diluted (in dollars per share)	$ 2.33	$ 2.12
2024 Acquisitions \| Fair Value Adjustment to Inventory
Pro Forma Information
Increase (decrease) in cost of revenue		$ 2,331
2024 Acquisitions \| Adjustment, Fair Value Adjustment To Inventory
Pro Forma Information
Increase (decrease) in cost of revenue	$ (2,331)
2024 Acquisitions \| Acquisition-Related Costs And Intangible Asset Amortization
Pro Forma Information
Increase (decrease) in selling, general, and administrative expenses		$ 1,923
2024 Acquisitions \| Adjustment, Acquisition-Related Costs And Intangible Asset Amortization
Pro Forma Information
Increase (decrease) in selling, general, and administrative expenses	$ (1,923)

Business Acquisition, Pro Forma Earnings Per Share [Abstract]

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The pro forma basic net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

+ References

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The pro forma diluted net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

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The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

+ References

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The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

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The aggregate costs related to goods produced and sold and services rendered by an entity during the reporting period. This excludes costs incurred during the reporting period related to financial services rendered and other revenue generating activities.

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The aggregate total costs related to selling a firm's product and services, as well as all other general and administrative expenses. Direct selling expenses (for example, credit, warranty, and advertising) are expenses that can be directly linked to the sale of specific products. Indirect selling expenses are expenses that cannot be directly linked to the sale of specific products, for example telephone expenses, Internet, and postal charges. General and administrative expenses include salaries of non-sales personnel, rent, utilities, communication, etc.

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