Accounts Receivable (Allowance for Doubtful Accounts Rollforward) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 548	$ 22	$ 36
Provision adjustment - expense, net of recoveries	62	599	23
Write-offs and other adjustments - deductions to receivable balances	(462)	(73)	(37)
Balance at end of period	$ 148	$ 548	$ 22