Property, Plant, and Equipment, Net (Narrative) (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
Jun. 30, 2016	Sep. 30, 2016	Sep. 30, 2015
Construction in progress	$ 138,798		$ 252,763
Property, plant and equipment held for sale			681
Service Life [Member]
Change in accounting estimate, financial effect - depreciation expense		$12,000
Second Campus Rockford Illinois [Member]
Construction in progress	66,695		47,629
Capitalized interest	1,469		499
New Campus Fort Collins Colorado [Member]
Construction in progress	4,554		151,669
Capitalized interest	284		$ 5,205
Building and Building Improvements [Member] \| New Campus Fort Collins Colorado [Member]
Contruction in progress placed into service	158,000
Office furniture and equipment [Member]
Gross assets acquired on capital leases	$ 1,626

Amount before accumulated depreciation of leased physical assets used in the normal conduct of business to produce goods and services.

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Amount of structure or a modification to a structure under construction. Includes recently completed structures or modifications to structures that have not been placed into service.

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Amount classified as property, plant and equipment attributable to disposal group held for sale or disposed of, expected to be disposed of after one year or the normal operating cycle, if longer.

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Amount of reclassification, impairment, donation, or other change to long-lived, 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, furniture and fixtures, and computer equipment.

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