Income Taxes (Components of Provision (Benefit)) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Current:
Domestic federal									$ 54	$ 530	$ (320)
Foreign									1,330	500	500
Foreign withholding taxes									240	280	1,240
Domestic state									120	110	0
Total current									1,744	1,420	1,420
Deferred:
Domestic federal									0	1,680	720
Foreign									0	0	(210)
Domestic state									0	0	(20)
Total deferred									0	1,680	490
Total provision	$ 474	$ 986	$ 194	$ 90	$ 1,060	$ 70	$ 1,670	$ 300	$ 1,744	$ 3,100	$ 1,910