EMPLOYEE STOCK PLANS - Net Share-Based Compensation Expense (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 29, 2019	Mar. 30, 2018	Mar. 29, 2019	Mar. 30, 2018
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation expense	$ 12.5	$ 10.5	$ 23.0	$ 21.2
Income tax benefit for share-based compensation	(2.2)	(2.6)	(4.5)	(4.7)
Cost of revenues - Product
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation expense	0.8	0.8	1.5	1.5
Cost of revenues - Service
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation expense	1.0	1.0	2.1	2.0
Research and development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation expense	1.1	1.2	2.2	2.4
Selling, general and administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation expense	$ 9.6	$ 7.5	$ 17.2	$ 15.3