Employee Benefit Plans - Post-Retirement Welfare Benefits Plan (Details) - Post Retirement Welfare Benefits Plan	12 Months Ended
Jan. 02, 2016 USD ($)
Defined Contribution Plan Disclosure [Line Items]
Maximum monthly contributions per employee	$ 358
Percentage paid by Kadant for Welfare Benefits Plan members with retirement date prior to January 1, 2005	75.00%
Percentage paid by Kadant for Welfare Benefits Plan members with retirement date after January 1, 2005	50.00%

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.

No definition available.

Name:	us-gaap_DefinedContributionPlanDisclosureLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration