SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Recently Adopted Accounting Pronouncements (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 27, 2019	Jul. 03, 2020	Jan. 03, 2020	Sep. 28, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201602Member
Operating lease right-of-use assets	$ 0.0	$ 29.6
Finance lease right-of-use assets		0.6
Operating lease liability		29.7
Present value of lease liabilities		0.6
Decrease to retained earnings upon adoption of new accounting guidance	$ (74.4)	$ (42.6)
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets				$ 26.8
Finance lease right-of-use assets				0.6
Operating lease liability				27.5
Present value of lease liabilities				0.6
Decrease to retained earnings upon adoption of new accounting guidance			$ (0.3)	$ 0.3