Property, Plant, and Equipment, Net (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016	Sep. 30, 2016
Construction in progress	$ 108,020		$ 108,020		$ 88,909
Depreciation expense	13,663	$ 8,633	26,118	$ 18,749
Second Campus Rockford Illinois [Member]
Construction in progress	41,941		41,941		26,741
Office furniture and equipment [Member]
Gross assets acquired on capital leases	1,653		1,653
Accumulated depreciation on capital lease assets	$ 530		$ 530		$ 322