ACCRUED EXPENSES, INCOME TAXES PAYABLE AND OTHER CURRENT LIABILITIES (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Sep. 30, 2016
ACCRUED EXPENSES, INCOME TAXES PAYABLE AND OTHER CURRENT LIABILITIES [Abstract]
Accrued compensation	$ 25,677	$ 17,856
Income taxes payable	5,606	7,878
Dividends payable	5,267	4,502
Raw materials received, not yet invoiced	3,731	2,648
Deferred revenue and customer advances	1,264	782
Warranty accrual	249	243
Taxes, other than income taxes	1,583	775
Current portion of long-term contract liability	1,500	1,500
Other accrued expenses	4,418	5,211
Total	$ 49,295	$ 41,395