Property, Plant, and Equipment, net (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Property, Plant and Equipment [Line Items]
Gain from change in estimate on ARO obligation					$ 2,879
Decrease in property, plant, and equipment					(2,100)
Asset retirement obligation, revision in estimated cash flows	$ 0	$ 0	$ 0	$ 845	845	$ 0	$ 0
Depreciation					$ 2,100	$ 2,500	$ 2,400
Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Decrease in property, plant, and equipment				(4,000)
Accumulated Depreciation [Member]
Property, Plant and Equipment [Line Items]
Decrease in property, plant, and equipment				$ (1,900)