Earnings per Share - Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Oct. 01, 2022	Sep. 30, 2023	Oct. 01, 2022
Income Amounts Attributable to Parent, Disclosures [Abstract]
Net Income Attributable to Kadant	$ 30,864	$ 27,487	$ 88,673	$ 94,849
Basic Weighted Average Shares	11,706	11,662	11,697	11,651
Effect of Restricted Stock Units and Employee Stock Purchase Plan Shares	34	38	22	30
Diluted Weighted Average Shares	11,740	11,700	11,719	11,681
Basic Earnings per Share (in dollars per share)	$ 2.64	$ 2.36	$ 7.58	$ 8.14
Diluted Earnings per Share (in dollars per share)	$ 2.63	$ 2.35	$ 7.57	$ 8.12