Accounts Receivable (Allowance for Doubtful Accounts Rollforward) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at beginning of period		$ 33	$ 22	$ 36
Provision adjustment - expense, net of recoveries	$ 58	7	75	7
Write-offs and other adjustments - deductions to receivable balances	(2)	(27)	(2)	(30)
Balance at end of period	$ 95	$ 13	$ 95	$ 13