Segments and Disaggregated Revenue - Schedule of Disaggregation of Net Sales by Segment (Details) - Sales Revenue, Net - Product Concentration Risk	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
SBS
Disaggregation Of Revenue [Line Items]
Percentage of net sales	100.00%	100.00%	100.00%
SBS \| Hair color
Disaggregation Of Revenue [Line Items]
Percentage of net sales	40.00%	39.90%	38.20%
SBS \| Hair care
Disaggregation Of Revenue [Line Items]
Percentage of net sales	24.40%	23.90%	23.60%
SBS \| Styling tools and supplies
Disaggregation Of Revenue [Line Items]
Percentage of net sales	16.80%	17.90%	19.10%
SBS \| Nail
Disaggregation Of Revenue [Line Items]
Percentage of net sales	10.30%	10.10%	10.80%
SBS \| Skin and cosmetics
Disaggregation Of Revenue [Line Items]
Percentage of net sales	7.90%	7.60%	7.60%
SBS \| Other Beauty items
Disaggregation Of Revenue [Line Items]
Percentage of net sales	0.60%	0.60%	0.70%
SBS \| Sales channel, directly to consumer \| Company-operated stores
Disaggregation Of Revenue [Line Items]
Percentage of net sales	93.10%	93.80%	94.00%
SBS \| Sales channel, through intermediary \| E-commerce
Disaggregation Of Revenue [Line Items]
Percentage of net sales	6.90%	6.20%	6.00%
BSG
Disaggregation Of Revenue [Line Items]
Percentage of net sales	100.00%	100.00%	100.00%
BSG \| Hair color
Disaggregation Of Revenue [Line Items]
Percentage of net sales	41.00%	40.20%	39.00%
BSG \| Hair care
Disaggregation Of Revenue [Line Items]
Percentage of net sales	42.20%	42.30%	43.50%
BSG \| Styling tools and supplies
Disaggregation Of Revenue [Line Items]
Percentage of net sales	10.50%	10.60%	10.90%
BSG \| Nail
Disaggregation Of Revenue [Line Items]
Percentage of net sales	2.50%	2.70%	2.40%
BSG \| Skin and cosmetics
Disaggregation Of Revenue [Line Items]
Percentage of net sales	3.60%	3.90%	3.80%
BSG \| Other Beauty items
Disaggregation Of Revenue [Line Items]
Percentage of net sales	0.20%	0.30%	0.40%
BSG \| Sales channel, directly to consumer \| Company-operated stores
Disaggregation Of Revenue [Line Items]
Percentage of net sales	68.40%	67.20%	66.40%
BSG \| Sales channel, through intermediary \| E-commerce
Disaggregation Of Revenue [Line Items]
Percentage of net sales	13.60%	13.50%	12.30%
BSG \| Sales channel, through intermediary \| Franchise stores
Disaggregation Of Revenue [Line Items]
Percentage of net sales	7.40%	7.50%	7.40%
BSG \| Sales channel, through intermediary \| Distributor sales consultants
Disaggregation Of Revenue [Line Items]
Percentage of net sales	10.60%	11.80%	13.90%