Accounts Receivable (Allowance for Doubtful Accounts Rollforward) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at beginning of period	$ 36	$ 462	$ 116
Provision adjustment - expense, net of recoveries	23	23	556
Write-offs and other adjustments - deductions to receivable balances	(37)	(449)	(210)
Balance at end of period	$ 22	$ 36	$ 462