ACCRUED EXPENSES, INCOME TAXES PAYABLE AND OTHER CURRENT LIABILITIES (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Sep. 30, 2017
ACCRUED EXPENSES, INCOME TAXES PAYABLE AND OTHER CURRENT LIABILITIES [Abstract]
Accrued compensation	$ 21,303	$ 35,332
Income taxes payable	14,055	9,717
Dividends payable	5,337	5,314
Goods and services received, not yet invoiced	4,968	2,172
Deferred revenue and customer advances	2,491	1,559
Warranty accrual	236	247
Taxes, other than income taxes	1,858	1,688
Current portion of long-term contract liability	1,500	1,500
Other accrued expenses	6,972	5,122
Total	$ 58,720	$ 62,651