Income Taxes (Components of Provision (Benefit)) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Current:
Domestic federal									$ 1,167	$ 54	$ 530
Foreign									(1,404)	1,330	500
Foreign withholding taxes									356	240	280
Domestic state									101	120	110
Total current									220	1,744	1,420
Deferred:
Domestic federal									0	0	1,680
Total deferred									0	0	1,680
Total provision	$ 370	$ 1,390	$ (2,780)	$ 1,240	$ 474	$ 986	$ 194	$ 90	$ 220	$ 1,744	$ 3,100