Condensed Consolidated Statement of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 28, 2020	Mar. 30, 2019
Income Statement [Abstract]
Revenue (Notes 1 and 10)	$ 159,127	$ 171,316
Costs and Operating Expenses:
Cost of revenue	90,804	100,801
Selling, general, and administrative expenses	45,592	49,319
Research and development expenses	3,076	2,621
Total Costs and Operating Expenses	139,472	152,741
Operating Income	19,655	18,575
Interest Income	51	56
Interest Expense	(2,459)	(3,504)
Other Expense, Net	(32)	(99)
Income Before Provision for Income Taxes	17,215	15,028
Provision for Income Taxes (Note 3)	4,559	3,963
Net Income	12,656	11,065
Net Income Attributable to Noncontrolling Interest	(125)	(165)
Net Income Attributable to Kadant	$ 12,531	$ 10,900
Earnings per Share Attributable to Kadant (Note 2)
Basic (in dollars per share)	$ 1.10	$ 0.98
Diluted (in dollars per share)	$ 1.09	$ 0.96
Weighted Average Shares (Note 2)
Basic (in shares)	11,432	11,133
Diluted (in shares)	11,508	11,385