SEGMENT INFORMATION (Capital expenditures, depreciation and amortization expense by segment) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jul. 03, 2021	Jun. 27, 2020	Jul. 03, 2021	Jun. 27, 2020
Segment Reporting, Other Significant Reconciling Item [Line Items]
Capital expenditures	$ 7,956	$ 3,451	$ 16,763	$ 8,550
Depreciation and amortization expense:
Depreciation expense	3,465	3,255	9,899	9,146
Amortization expense	1,340	1,814	4,653	5,451
Capital Equipment
Segment Reporting, Other Significant Reconciling Item [Line Items]
Capital expenditures	5,526	1,329	11,120	3,215
Depreciation and amortization expense:
Depreciation expense	1,668	1,713	4,850	4,747
Amortization expense	845	973	2,751	2,925
APS
Segment Reporting, Other Significant Reconciling Item [Line Items]
Capital expenditures	2,430	2,122	5,643	5,335
Depreciation and amortization expense:
Depreciation expense	1,797	1,542	5,049	4,399
Amortization expense	$ 495	$ 841	$ 1,902	$ 2,526