SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Additional Information (Detail)	3 Months Ended		8 Months Ended	12 Months Ended
	Sep. 30, 2019 USD ($) item shares	Sep. 30, 2018 USD ($) shares	Feb. 28, 2019	Jun. 30, 2019 USD ($)	Jul. 01, 2019 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Revenue recognized included in the deferred revenue	$ 79,400,000
Allowance for bad debts	18,800,000	$ 13,300,000		$ 14,500,000
Capitalized internal-use software development costs	11,100,000	12,400,000		10,600,000
Property, Plant and Equipment, Gross	$ 595,042,000	$ 576,714,000		606,673,000
Number of Operating Units Benefit from Local Tax Incentives | item	3
Decrease in noncontrolling interest	$ 6,247,000
Anti-dilutive shares excluded from computations of earnings per share | shares	329,000	272,000
Discount on re-issue of treasury stock			5.00%
Cumulative translation losses	$ 176,900,000	$ 163,200,000		137,400,000
Advertising expense	20,200,000	16,800,000
Operating Lease Assets	195,238,000	0		0
Hurricane [Member]
Summary Of Significant Accounting Policies [Line Items]
Loss from catastrophes	0	6,900,000
Unusual or Infrequent Item, or Both, Insurance Proceeds		6,900,000
DeVry University And Carrington College [Member]
Summary Of Significant Accounting Policies [Line Items]
Impairment of Long-Lived Assets to be Disposed of		2,200,000
Property, Plant and Equipment, Gross		0
ASC 842
Summary Of Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Gross					$ 725,713,000
Operating Lease Assets					282,978,000
ASC 842 | Adjustments due to adoption of ASC 842
Summary Of Significant Accounting Policies [Line Items]
Operating Lease Assets					$ 282,978,000
Parent [Member]
Summary Of Significant Accounting Policies [Line Items]
Cumulative translation losses	176,600,000	159,400,000		134,300,000
Tax effect on unrealized gains on available-for-sale securities	100,000			100,000
Other comprehensive income (loss), securities available-for-sale, tax	0.0			0.0
Noncontrolling Interest [Member]
Summary Of Significant Accounting Policies [Line Items]
Cumulative translation losses	$ 300,000	3,800,000		$ 3,100,000
Maximum
Summary Of Significant Accounting Policies [Line Items]
Revenue practical expedient remaining performance obligation	1 year
Software and Software Development Costs [Member] | Maximum
Summary Of Significant Accounting Policies [Line Items]
Finite live intangible assets amortization period	7 years
Adtalem Brazil [Member]
Summary Of Significant Accounting Policies [Line Items]
Ownership interest of parent in subsidiary	100.00%			97.90%
Decrease in noncontrolling interest	$ 6,200,000
Adtalem Brazil Senior Management Group [Member] | Adtalem Brazil [Member]
Summary Of Significant Accounting Policies [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners				2.10%
Edupristine [Member]
Summary Of Significant Accounting Policies [Line Items]
Ownership interest of parent in subsidiary	69.00%
Ownership percentage held by minority available for purchase	33.00%
Kaizen [Member] | Edupristine [Member]
Summary Of Significant Accounting Policies [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	31.00%
Dominica Campus [Member] | Ross University School of Medicine [Member]
Summary Of Significant Accounting Policies [Line Items]
Impairment of Long-Lived Assets to be Disposed of		$ 37,800,000
Property, Plant and Equipment, Gross	$ 0