Parent, Issuers, Guarantor and Non-Guarantor Condensed Consolidating Financial Statements - Condensed Consolidating Balance Sheet (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018
Assets
Cash and cash equivalents	$ 364,414		$ 71,495	$ 89,777		$ 77,295
Trade and other accounts receivable, net	87,333		104,539
Inventory	946,189		952,907
Other current assets	51,103		34,612
Property and equipment, net	320,220		319,628
Operating lease assets	544,471
Goodwill and other intangible assets, net	587,930		592,837
Other assets	19,506		22,428
Total assets	2,921,166		2,098,446
Liabilities and Stockholders’ Equity (Deficit)
Accounts payable	221,760		278,688
Accrued liabilities	145,920		169,054
Income taxes payable	1,323		8,336
Long-term debt	1,945,866		1,594,543
Long-term operating lease liabilities	556,755
Other liabilities	18,310		27,757
Deferred income tax liabilities, net	84,427		80,391
Total liabilities	2,974,361		2,158,769
Total stockholders’ equity (deficit)	(53,195)	$ 2,199	(60,323)	(145,075)	$ (214,731)	(268,556)
Total liabilities and stockholders’ deficit	2,921,166		2,098,446
Parent
Assets
Other current assets	15,311		1,436
Property and equipment, net	8		6
Investment in subsidiaries	1,685,104		1,621,843
Other assets	1,446		1,446
Total assets	1,701,869		1,624,731
Liabilities and Stockholders’ Equity (Deficit)
Accounts payable	23		48
Due to affiliates	1,748,579		1,672,322
Accrued liabilities	160		188
Income taxes payable			6,055
Other liabilities	6,441		6,441
Deferred income tax liabilities, net	(139)
Total liabilities	1,755,064		1,685,054
Total stockholders’ equity (deficit)	(53,195)		(60,323)
Total liabilities and stockholders’ deficit	1,701,869		1,624,731
Sally Holdings and Sally Capital
Assets
Cash and cash equivalents	10		10	10		10
Other current assets	270		132
Investment in subsidiaries	4,469,936		4,374,334
Other assets	3,092		3,499
Total assets	4,473,308		4,377,975
Liabilities and Stockholders’ Equity (Deficit)
Due to affiliates	823,032		1,142,324
Accrued liabilities	18,151		17,937
Income taxes payable	2,161		2,161
Long-term debt	1,945,023		1,593,710
Deferred income tax liabilities, net	(163)
Total liabilities	2,788,204		2,756,132
Total stockholders’ equity (deficit)	1,685,104		1,621,843
Total liabilities and stockholders’ deficit	4,473,308		4,377,975
Guarantor Subsidiaries
Assets
Cash and cash equivalents	335,827		41,009	49,719		29,050
Trade and other accounts receivable, net	52,788		65,746
Due from affiliates	2,638,162		2,878,072
Inventory	710,623		722,830
Other current assets	23,119		22,480
Property and equipment, net	264,739		258,132
Operating lease assets	401,374
Investment in subsidiaries	376,173		385,629
Goodwill and other intangible assets, net	450,484		452,645
Other assets	3,098		(581)
Total assets	5,256,387		4,825,962
Liabilities and Stockholders’ Equity (Deficit)
Accounts payable	180,078		235,940
Accrued liabilities	100,226		121,375
Income taxes payable			1
Long-term debt	4		1
Long-term operating lease liabilities	413,824
Other liabilities	11,840		17,639
Deferred income tax liabilities, net	80,479		76,672
Total liabilities	786,451		451,628
Total stockholders’ equity (deficit)	4,469,936		4,374,334
Total liabilities and stockholders’ deficit	5,256,387		4,825,962
Non-Guarantor Subsidiaries
Assets
Cash and cash equivalents	28,577		30,476	$ 40,048		$ 48,235
Trade and other accounts receivable, net	34,545		38,793
Inventory	235,566		230,077
Other current assets	12,403		10,564
Property and equipment, net	55,473		61,490
Operating lease assets	143,097
Goodwill and other intangible assets, net	137,446		140,192
Other assets	11,870		18,064
Total assets	658,977		529,656
Liabilities and Stockholders’ Equity (Deficit)
Accounts payable	41,659		42,700
Due to affiliates	66,551		63,426
Accrued liabilities	27,383		29,554
Income taxes payable	(838)		119
Long-term debt	839		832
Long-term operating lease liabilities	142,931
Other liabilities	29		3,677
Deferred income tax liabilities, net	4,250		3,719
Total liabilities	282,804		144,027
Total stockholders’ equity (deficit)	376,173		385,629
Total liabilities and stockholders’ deficit	658,977		529,656
Consolidating Eliminations
Assets
Due from affiliates	(2,638,162)		(2,878,072)
Investment in subsidiaries	(6,531,213)		(6,381,806)
Total assets	(9,169,375)		(9,259,878)
Liabilities and Stockholders’ Equity (Deficit)
Due to affiliates	(2,638,162)		(2,878,072)
Total liabilities	(2,638,162)		(2,878,072)
Total stockholders’ equity (deficit)	(6,531,213)		(6,381,806)
Total liabilities and stockholders’ deficit	$ (9,169,375)		$ (9,259,878)