INCOME TAXES - Provision for Income Taxes (Details)		12 Months Ended
	Jan. 01, 2018	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Federal statutory rate	21.00%	21.00%	21.00%	24.50%
U.S. benefits from research and experimentation activities		(1.50%)	(2.90%)	(0.80%)
State taxes, net of federal effect		1.10%	(4.70%)	0.10%
Foreign income at other than U.S. rates		1.70%	10.30%	1.20%
Excess compensation		0.40%	6.40%	0.40%
Share-based compensation		(2.20%)	(7.20%)	(4.30%)
U.S. tax reform		0	0.141	0.112
Global Intangible Low Taxed Income ("GILTI")		0.00%	3.10%	0.00%
Foreign derived intangible income		(3.40%)	(3.90%)	0.00%
Change in reserve positions		1.90%	0.30%	(0.50%)
Other, net		(1.40%)	1.40%	0.20%
Provision for income taxes		17.60%	37.90%	32.00%