INCOME TAXES, Components of Net Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Deferred tax assets [Abstract]
Employee benefits	$ 3,995	$ 5,307
Inventory	2,526	2,863
Bad debt reserve	361	585
Share-based compensation expense	5,379	6,611
Credit and other carryforwards	6,419	22,663
Other	1,336	1,488
Valuation allowance	(133)	(2,271)
Total deferred tax assets	19,883	37,246
Deferred tax liabilities [Abstract]
Depreciation and amortization	8,007	14,671
Translation adjustment	0	300
Withholding on transition taxes	5,209	0
Other	908	739
Total deferred tax liabilities	$ 14,124	$ 15,710