Segment Reporting - Schedule of Disaggregation of Net Sales by Segment (Details) - Sales Revenue, Net - Product Concentration Risk	3 Months Ended		9 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
SBS
Disaggregation Of Revenue [Line Items]
Percentage of Net Sales	100.00%	100.00%	100.00%	100.00%
SBS \| Sales Channel, Directly to Consumer \| Company-operated stores
Disaggregation Of Revenue [Line Items]
Percentage of Net Sales	90.30%	91.80%	90.40%	91.90%
SBS \| Sales Channel, Through Intermediary \| E-commerce
Disaggregation Of Revenue [Line Items]
Percentage of Net Sales	9.70%	8.20%	9.60%	8.10%
SBS \| Hair color
Disaggregation Of Revenue [Line Items]
Percentage of Net Sales	45.20%	42.90%	44.40%	41.90%
SBS \| Hair care
Disaggregation Of Revenue [Line Items]
Percentage of Net Sales	21.20%	23.00%	21.60%	23.50%
SBS \| Styling tools and supplies
Disaggregation Of Revenue [Line Items]
Percentage of Net Sales	15.80%	16.20%	16.40%	16.90%
SBS \| Skin and cosmetics
Disaggregation Of Revenue [Line Items]
Percentage of Net Sales	7.60%	7.50%	7.40%	7.50%
SBS \| Nail
Disaggregation Of Revenue [Line Items]
Percentage of Net Sales	10.00%	10.20%	9.90%	10.00%
SBS \| Other beauty items
Disaggregation Of Revenue [Line Items]
Percentage of Net Sales	0.20%	0.20%	0.30%	0.20%
BSG
Disaggregation Of Revenue [Line Items]
Percentage of Net Sales	100.00%	100.00%	100.00%	100.00%
BSG \| Sales Channel, Directly to Consumer \| Company-operated stores
Disaggregation Of Revenue [Line Items]
Percentage of Net Sales	69.20%	69.50%	69.20%	69.40%
BSG \| Sales Channel, Through Intermediary \| E-commerce
Disaggregation Of Revenue [Line Items]
Percentage of Net Sales	14.60%	13.70%	14.70%	13.90%
BSG \| Sales Channel, Through Intermediary \| Salon business consultants
Disaggregation Of Revenue [Line Items]
Percentage of Net Sales	8.60%	9.20%	8.50%	9.40%
BSG \| Sales Channel, Through Intermediary \| Franchise stores
Disaggregation Of Revenue [Line Items]
Percentage of Net Sales	7.60%	7.60%	7.60%	7.30%
BSG \| Hair color
Disaggregation Of Revenue [Line Items]
Percentage of Net Sales	44.30%	43.00%	43.30%	41.90%
BSG \| Hair care
Disaggregation Of Revenue [Line Items]
Percentage of Net Sales	40.60%	41.60%	41.40%	41.80%
BSG \| Styling tools and supplies
Disaggregation Of Revenue [Line Items]
Percentage of Net Sales	9.70%	9.90%	10.00%	10.40%
BSG \| Skin and cosmetics
Disaggregation Of Revenue [Line Items]
Percentage of Net Sales	3.00%	3.20%	3.10%	3.50%
BSG \| Nail
Disaggregation Of Revenue [Line Items]
Percentage of Net Sales	2.30%	2.20%	2.10%	2.30%
BSG \| Other beauty items
Disaggregation Of Revenue [Line Items]
Percentage of Net Sales	0.10%	0.10%	0.10%	0.10%