SHAREHOLDERS' EQUITY AND EMPLOYEE BENEFIT PLANS (Total equity-based compensation expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 28, 2019	Sep. 29, 2018		Sep. 30, 2017
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total equity-based compensation expense (reversal)	$ 14,332	$ 11,685	[1]	$ 11,722
Market-based restricted stock [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total equity-based compensation expense (reversal)	4,220	3,583		3,480
Time-based restricted stock [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total equity-based compensation expense (reversal)	8,603	7,027		7,492
Stock options [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total equity-based compensation expense (reversal)	675	295		0
Common Stock
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total equity-based compensation expense (reversal)	834	780		750
Cost of sales [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total equity-based compensation expense (reversal)	632	515		463
Selling, general and administrative (1) [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total equity-based compensation expense (reversal)	10,503	8,548		9,015
Research and development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total equity-based compensation expense (reversal)	$ 3,197	$ 2,622		$ 2,244

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