STOCK-BASED COMPENSATION (Allocation of Recognized Period Costs) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 03, 2026	Jun. 27, 2025	Jul. 03, 2026	Jun. 27, 2025
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 5,383	$ 5,656	$ 12,045	$ 12,536
Location, Statement of Income, Balance [Axis]: us-gaap:CostOfGoodsAndServicesSold
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	1,129	1,083	2,537	2,506
Location, Statement of Income, Balance [Axis]: us-gaap:ResearchAndDevelopmentExpenseExcludingAcquiredInProcessCost
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	268	267	603	647
Location, Statement of Income, Balance [Axis]: us-gaap:SellingGeneralAndAdministrativeExpense
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	3,854	4,360	8,558	9,408
Location, Statement of Income, Balance [Axis]: itgr:RestructuringAndOtherChargesNet
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 132	$ (54)	$ 347	$ (25)