Separate Financial Information of Guarantor Subsidiaries - Condensed Consolidating Statement of Earnings and Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Condensed Income Statements Captions [Line Items]
Net sales	$ 965,937	$ 975,169	$ 945,852	$ 989,453	$ 965,997	$ 996,283	$ 975,321	$ 994,964	$ 3,876,411	$ 3,932,565	$ 3,938,317
Cost of goods sold									1,965,869	1,988,152	1,973,422
Gross profit	479,291	482,222	468,324	480,705	478,092	493,370	486,322	486,629	1,910,542	1,944,413	1,964,895
Selling, general and administrative expenses									1,452,751	1,484,209	1,463,619
Restructuring									(682)	33,615	22,679
Operating earnings									458,473	426,589	478,597
Interest expense (income)									96,309	98,162	132,899
Earnings before provision for income taxes									362,164	328,427	345,698
Provision (benefit) for income taxes									90,541	70,380	130,622
Net earnings	$ 69,007	$ 71,164	$ 65,725	$ 65,727	$ 55,186	$ 58,226	$ 61,371	$ 83,264	271,623	258,047	215,076
Other comprehensive income (loss), net of tax									(27,296)	(8,155)	18,215
Total comprehensive income									244,327	249,892	233,291
Parent
Condensed Income Statements Captions [Line Items]
Selling, general and administrative expenses									11,331	10,957	10,939
Operating earnings									(11,331)	(10,957)	(10,939)
Earnings before provision for income taxes									(11,331)	(10,957)	(10,939)
Provision (benefit) for income taxes									(2,742)	(2,734)	(4,246)
Equity in earnings of subsidiaries, net of tax									280,212	266,270	221,769
Net earnings									271,623	258,047	215,076
Total comprehensive income									271,623	258,047	215,076
Sally Holdings and Sally Capital
Condensed Income Statements Captions [Line Items]
Selling, general and administrative expenses									607	1,538	526
Operating earnings									(607)	(1,538)	(526)
Interest expense (income)									96,464	98,332	132,696
Earnings before provision for income taxes									(97,071)	(99,870)	(133,222)
Provision (benefit) for income taxes									(24,888)	(28,787)	(51,726)
Equity in earnings of subsidiaries, net of tax									352,395	337,353	303,265
Net earnings									280,212	266,270	221,769
Other comprehensive income (loss), net of tax									(4,566)	2,449	(1,084)
Total comprehensive income									275,646	268,719	220,685
Guarantor Subsidiaries
Condensed Income Statements Captions [Line Items]
Net sales									3,131,360	3,152,120	3,209,039
Related party sales									2,201	2,294	2,501
Cost of goods sold									1,568,663	1,581,385	1,590,184
Gross profit									1,564,898	1,573,029	1,621,356
Selling, general and administrative expenses									1,135,926	1,136,312	1,130,615
Restructuring									(682)	33,615	22,679
Operating earnings									429,654	403,102	468,062
Interest expense (income)									5	(3)	6
Earnings before provision for income taxes									429,649	403,105	468,056
Provision (benefit) for income taxes									109,230	73,747	177,383
Equity in earnings of subsidiaries, net of tax									31,976	7,995	12,592
Net earnings									352,395	337,353	303,265
Total comprehensive income									352,395	337,353	303,265
Non-Guarantor Subsidiaries
Condensed Income Statements Captions [Line Items]
Net sales									745,051	780,445	729,278
Cost of goods sold									399,407	409,061	385,739
Gross profit									345,644	371,384	343,539
Selling, general and administrative expenses									304,887	335,402	321,539
Operating earnings									40,757	35,982	22,000
Interest expense (income)									(160)	(167)	197
Earnings before provision for income taxes									40,917	36,149	21,803
Provision (benefit) for income taxes									8,941	28,154	9,211
Net earnings									31,976	7,995	12,592
Other comprehensive income (loss), net of tax									(22,730)	(10,604)	19,299
Total comprehensive income									9,246	(2,609)	31,891
Consolidating Eliminations
Condensed Income Statements Captions [Line Items]
Related party sales									(2,201)	(2,294)	(2,501)
Cost of goods sold									(2,201)	(2,294)	(2,501)
Equity in earnings of subsidiaries, net of tax									(664,583)	(611,618)	(537,626)
Net earnings									(664,583)	(611,618)	(537,626)
Total comprehensive income									$ (664,583)	$ (611,618)	$ (537,626)