Unaudited Quarterly Information (Details) (USD $)	3 Months Ended											12 Months Ended
	Dec. 29, 2012	Sep. 29, 2012		Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011		Oct. 01, 2011		Jul. 02, 2011	Apr. 02, 2011	Dec. 29, 2012	Dec. 31, 2011	Jan. 01, 2011
Unaudited Quarterly Information [Abstract]
Revenues	$ 78,055,000	$ 86,601,000		$ 82,982,000	$ 84,113,000	$ 96,965,000		$ 84,358,000		$ 82,457,000	$ 71,680,000	$ 331,751,000	$ 335,460,000	$ 270,029,000
Gross profit	33,536,000	37,596,000		36,298,000	38,372,000	37,403,000		36,011,000		37,706,000	34,093,000
Amounts Attributable to Kadant [Abstract]
Income from Continuing Operations	9,603,000	7,617,000		6,546,000	7,114,000	10,676,000		9,804,000	[1]	7,309,000	5,795,000	30,880,000	33,584,000	18,409,000
(Loss) Income from Discontinued Operation	(37,000)	844,000	[2]	(3,000)	(61,000)	1,156,000	[3]	(1,156,000)	[3]	(5,000)	(4,000)	743,000	(9,000)	98,000
Net Income Attributable to Kadant	9,566,000	8,461,000		6,543,000	7,053,000	11,832,000		8,648,000		7,304,000	5,791,000	31,623,000	33,575,000	18,507,000
Basic Earnings Per Share [Abstract]
Continuing Operations (in dollars per share)	$ 0.85	$ 0.67		$ 0.57	$ 0.61	$ 0.91		$ 0.81		$ 0.59	$ 0.47	$ 2.70	$ 2.77	$ 1.49
Net Income Attributable to Kadant (in dollars per share)	$ 0.85	$ 0.75		$ 0.57	$ 0.61	$ 1.01		$ 0.71		$ 0.59	$ 0.47	$ 2.76	$ 2.77	$ 1.50
Diluted Earnings Per Share [Abstract]
Continuing Operations (in dollars per share)	$ 0.84	$ 0.66		$ 0.56	$ 0.61	$ 0.90		$ 0.80		$ 0.59	$ 0.47	$ 2.66	$ 2.74	$ 1.48
Net Income Attributable to Kadant (in dollars per share)	$ 0.83	$ 0.74		$ 0.56	$ 0.60	$ 1.00		$ 0.70		$ 0.59	$ 0.47	$ 2.73	$ 2.74	$ 1.48
Pre-tax gain on sale of real estate								2,300,000
Warranty and legal provision, discontinued operation								1,200,000
Tax benefit						$ 1,200,000

[1] Includes a $2.3 million pre-tax gain on the sale of real estate in the third quarter of 2011.

[2] Includes a $1.5 million reduction to the estimated liability for the claims under the class action lawsuit in the third quarter of 2012.

[3] Includes a $1.2 million warranty and legal provision and a $1.2 million tax benefit in the third and fourth quarters of 2011, respectively.