Detail of Selected Balance Sheet Accounts - Activity in Allowance for Doubtful Accounts (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	$ 811	$ 746
Bad debt expense (recovery)	(160)	187	$ (29)
Uncollectible accounts written off, net of recoveries	(472)	(120)
Change due to foreign currency translation	0	(2)
Balance at end of period	$ 179	$ 811	$ 746