Goodwill and Intangible Assets (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2016	Jun. 30, 2015	Sep. 30, 2015	Dec. 31, 2013
Finite Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 89	$ 114		$ 263	$ 345
Cash received from amended supply agreement				2,333	2,333
Other current assets	2,978			$ 2,978		$ 3,916
Deferred credit amortization period				4 years
Gains in other income	507	$ 507		$ 1,522	1,893
General Electric Company
Finite Lived Intangible Assets [Line Items]
Cash received from amended supply agreement			$ 10,000
Additional amount paid on execution of agreement				$ 7,000
Acquired finite-lived intangible assets, period				3 years
Other current assets	$ 2,300			$ 2,300
Deferred credit							$ 8,100
Supply Agreement
Finite Lived Intangible Assets [Line Items]
Useful life of intangible asset				15 years
Other Income | General Electric Company
Finite Lived Intangible Assets [Line Items]
Gains in other income				$ 1,500	$ 1,500