Inventories (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Components of inventories
Raw materials and supplies	$ 6,108	$ 7,724
Work-in-process	7,650	10,459
Finished goods	6,623	10,313
Total inventories	20,381	28,496
Additional amount that would have been reported in inventory if FIFO method had been used	8,319	8,026
LIFO expense (income)	$ 293	$ (482)