Business Segments - Schedule of Disaggregation of Net Sales by Segment (Details) - Sales Revenue, Net	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Sally Beauty Supply
Disaggregation Of Revenue [Line Items]
Percentage of net sales	100.00%	100.00%	100.00%	100.00%
Sally Beauty Supply | Product Concentration Risk
Disaggregation Of Revenue [Line Items]
Percentage of net sales	100.00%	100.00%	100.00%	100.00%
Sally Beauty Supply | Hair color | Product Concentration Risk
Disaggregation Of Revenue [Line Items]
Percentage of net sales	35.10%	32.80%	35.30%	31.90%
Sally Beauty Supply | Hair care | Product Concentration Risk
Disaggregation Of Revenue [Line Items]
Percentage of net sales	18.60%	19.50%	18.60%	19.70%
Sally Beauty Supply | Skin and nail care | Product Concentration Risk
Disaggregation Of Revenue [Line Items]
Percentage of net sales	14.00%	12.80%	12.30%	13.50%
Sally Beauty Supply | Styling tools | Product Concentration Risk
Disaggregation Of Revenue [Line Items]
Percentage of net sales	12.20%	12.70%	14.40%	13.40%
Sally Beauty Supply | Salon supplies and accessories | Product Concentration Risk
Disaggregation Of Revenue [Line Items]
Percentage of net sales	8.20%	7.60%	7.80%	7.20%
Sally Beauty Supply | Textured hair products | Product Concentration Risk
Disaggregation Of Revenue [Line Items]
Percentage of net sales	6.40%	6.10%	6.00%	5.70%
Sally Beauty Supply | Other Beauty items | Product Concentration Risk
Disaggregation Of Revenue [Line Items]
Percentage of net sales	5.50%	8.50%	5.60%	8.60%
Sally Beauty Supply | Sales channel, directly to consumer | Company-operated stores
Disaggregation Of Revenue [Line Items]
Percentage of net sales	93.00%	94.90%	93.50%	95.40%
Sally Beauty Supply | Sales channel, through intermediary | E-commerce
Disaggregation Of Revenue [Line Items]
Percentage of net sales	6.90%	4.90%	6.50%	4.40%
Sally Beauty Supply | Sales channel, through intermediary | Franchise stores
Disaggregation Of Revenue [Line Items]
Percentage of net sales	0.10%	0.20%	0.00%	0.20%
Beauty Systems Group
Disaggregation Of Revenue [Line Items]
Percentage of net sales	100.00%	100.00%	100.00%	100.00%
Beauty Systems Group | Product Concentration Risk
Disaggregation Of Revenue [Line Items]
Percentage of net sales	100.00%	100.00%	100.00%	100.00%
Beauty Systems Group | Hair color | Product Concentration Risk
Disaggregation Of Revenue [Line Items]
Percentage of net sales	43.50%	40.10%	42.10%	38.80%
Beauty Systems Group | Hair care | Product Concentration Risk
Disaggregation Of Revenue [Line Items]
Percentage of net sales	37.60%	35.10%	36.30%	34.80%
Beauty Systems Group | Skin and nail care | Product Concentration Risk
Disaggregation Of Revenue [Line Items]
Percentage of net sales	7.20%	8.20%	7.70%	8.20%
Beauty Systems Group | Styling tools | Product Concentration Risk
Disaggregation Of Revenue [Line Items]
Percentage of net sales	6.20%	6.20%	6.60%	6.50%
Beauty Systems Group | Other Beauty items | Product Concentration Risk
Disaggregation Of Revenue [Line Items]
Percentage of net sales	2.40%	3.00%	2.60%	2.80%
Beauty Systems Group | Promotional items | Product Concentration Risk
Disaggregation Of Revenue [Line Items]
Percentage of net sales	3.10%	7.40%	4.70%	8.90%
Beauty Systems Group | Sales channel, directly to consumer | Company-operated stores
Disaggregation Of Revenue [Line Items]
Percentage of net sales	70.20%	70.40%	69.90%	69.80%
Beauty Systems Group | Sales channel, through intermediary | E-commerce
Disaggregation Of Revenue [Line Items]
Percentage of net sales	9.10%	5.90%	8.80%	5.70%
Beauty Systems Group | Sales channel, through intermediary | Franchise stores
Disaggregation Of Revenue [Line Items]
Percentage of net sales	7.00%	7.10%	7.30%	7.20%
Beauty Systems Group | Sales channel, through intermediary | Distributor sales consultants
Disaggregation Of Revenue [Line Items]
Percentage of net sales	13.70%	16.60%	14.00%	17.30%