Property and Equipment, net (Details) - USD ($) $ in Thousands	3 Months Ended
Dec. 31, 2019	Sep. 30, 2019
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 263,640	$ 305,657
Less accumulated depreciation and amortization	(189,825)	(201,531)
Property and equipment, net	73,815	104,126
Land
Property, Plant and Equipment [Line Items]
Property and equipment, gross	3,189	3,189
Buildings and building improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 26,504	82,653
Buildings and building improvements \| Minimum
Property, Plant and Equipment [Line Items]
Depreciable Lives	30 years
Buildings and building improvements \| Maximum
Property, Plant and Equipment [Line Items]
Depreciable Lives	35 years
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 67,592	53,020
Leasehold improvements \| Minimum
Property, Plant and Equipment [Line Items]
Depreciable Lives	1 year
Leasehold improvements \| Maximum
Property, Plant and Equipment [Line Items]
Depreciable Lives	28 years
Training equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 95,683	96,737
Training equipment \| Minimum
Property, Plant and Equipment [Line Items]
Depreciable Lives	3 years
Training equipment \| Maximum
Property, Plant and Equipment [Line Items]
Depreciable Lives	10 years
Office and computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 35,787	35,927
Office and computer equipment \| Minimum
Property, Plant and Equipment [Line Items]
Depreciable Lives	3 years
Office and computer equipment \| Maximum
Property, Plant and Equipment [Line Items]
Depreciable Lives	10 years
Curriculum development
Property, Plant and Equipment [Line Items]
Depreciable Lives	5 years
Property and equipment, gross	$ 19,692	19,692
Software developed for internal use
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 11,354	11,354
Software developed for internal use \| Minimum
Property, Plant and Equipment [Line Items]
Depreciable Lives	1 year
Software developed for internal use \| Maximum
Property, Plant and Equipment [Line Items]
Depreciable Lives	5 years
Vehicles
Property, Plant and Equipment [Line Items]
Depreciable Lives	5 years
Property and equipment, gross	$ 1,479	1,454
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 2,360	$ 1,631

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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