Note 6 - Acquisitions and Divestitures (Details Textual) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Jul. 30, 2021	Oct. 02, 2021	Sep. 26, 2020	Oct. 02, 2021	Sep. 26, 2020
Payment for Contingent Consideration Liability, Financing Activities				$ 494	$ 345
Revenue from Contract with Customer, Including Assessed Tax		$ 45,471	$ 31,561	138,953	109,246
Gain (Loss) on Disposition of Business		2,151	(0)	2,151	(0)
Engineering [Member]
Revenue from Contract with Customer, Including Assessed Tax		16,482	15,087	47,882	43,288
Gain (Loss) on Disposition of Business		2,151		2,151
Engineering [Member] | Pickering and Kincardine Offices [Member]
Revenue from Contract with Customer, Including Assessed Tax		500	$ 2,600	4,900	8,600
Gain (Loss) on Disposition of Business	$ 2,200
Escrow Deposit	$ 800
Sale of Assets, Escrow Deposit, Expected Period for Return of Deposit (Month)	18 months
PSR & TKE Acquisitions [Member]
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High		$ 2,400		2,400
Payment for Contingent Consideration Liability, Financing Activities				$ 500	$ 300