Earnings per Share - Computation (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended	12 Months Ended
Jan. 03, 2015	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 28, 2013	Sep. 28, 2013	Jun. 29, 2013	Mar. 30, 2013	Jan. 03, 2015	Dec. 28, 2013	Dec. 29, 2012
Earnings Per Share [Abstract]
Income from Continuing Operations	$ 9,106	$ 6,651	$ 7,867	$ 5,058	$ 5,935	$ 6,461	$ 5,772	$ 5,313	$ 28,682	$ 23,481	$ 30,880
(Loss) Income from Discontinued Operation									(23)	(62)	743
Net Income Attributable to Kadant	$ 9,101us-gaap_NetIncomeLoss	$ 6,647us-gaap_NetIncomeLoss	$ 7,858us-gaap_NetIncomeLoss	$ 5,053us-gaap_NetIncomeLoss	$ 5,928us-gaap_NetIncomeLoss	$ 6,447us-gaap_NetIncomeLoss	$ 5,760us-gaap_NetIncomeLoss	$ 5,284us-gaap_NetIncomeLoss	$ 28,659us-gaap_NetIncomeLoss	$ 23,419us-gaap_NetIncomeLoss	$ 31,623us-gaap_NetIncomeLoss
Basic Weighted Average Shares									10,988	11,153	11,456
Effect of Stock Options, Restricted Stock Units and Employee Stock Purchase Plan									222	187	134
Diluted Weighted Average Shares									11,210	11,340	11,590
Basic Earnings per Share:
Continuing Operations (in dollars per share)	$ 0.84	$ 0.61	$ 0.71	$ 0.45	$ 0.53	$ 0.58	$ 0.52	$ 0.48	$ 2.61	$ 2.11	$ 2.70
Discontinued Operation (in dollars per share)									$ 0.00	$ (0.01)	$ 0.06
Net Income per Basic Share (in dollars per share)	$ 0.84us-gaap_EarningsPerShareBasic	$ 0.61us-gaap_EarningsPerShareBasic	$ 0.71us-gaap_EarningsPerShareBasic	$ 0.45us-gaap_EarningsPerShareBasic	$ 0.53us-gaap_EarningsPerShareBasic	$ 0.58us-gaap_EarningsPerShareBasic	$ 0.52us-gaap_EarningsPerShareBasic	$ 0.47us-gaap_EarningsPerShareBasic	$ 2.61us-gaap_EarningsPerShareBasic	$ 2.10us-gaap_EarningsPerShareBasic	$ 2.76us-gaap_EarningsPerShareBasic
Diluted Earnings per Share:
Continuing Operations (in dollars per share)	$ 0.82	$ 0.60	$ 0.70	$ 0.45	$ 0.52	$ 0.57	$ 0.51	$ 0.47	$ 2.56	$ 2.07	$ 2.66
Discontinued Operation (in dollars per share)									$ 0.00	$ (0.01)	$ 0.06
Net Income per Diluted Share (in dollars per share)	$ 0.82us-gaap_EarningsPerShareDiluted	$ 0.60us-gaap_EarningsPerShareDiluted	$ 0.70us-gaap_EarningsPerShareDiluted	$ 0.45us-gaap_EarningsPerShareDiluted	$ 0.52us-gaap_EarningsPerShareDiluted	$ 0.57us-gaap_EarningsPerShareDiluted	$ 0.51us-gaap_EarningsPerShareDiluted	$ 0.47us-gaap_EarningsPerShareDiluted	$ 2.56us-gaap_EarningsPerShareDiluted	$ 2.07us-gaap_EarningsPerShareDiluted	$ 2.73us-gaap_EarningsPerShareDiluted

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Amount of income (loss) from continuing operations attributable to the parent. Also defined as revenue less expenses and taxes from ongoing operations before extraordinary items but after deduction of those portions of income or loss from continuing operations that are allocable to noncontrolling interests.

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The amount of net income (loss) from continuing operations per each share of common stock or unit outstanding during the reporting period.

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Amount of income (loss) from a disposal group, net of income tax, reported as a separate component of income before extraordinary items after deduction or consideration of the amount allocable to noncontrolling interests. Includes, net of tax, income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.

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Per basic share amount, after tax, of income (loss) from the day-to-day business activities of the discontinued operation and gain (loss) from the disposal of the discontinued operation.

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