ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Components of Accumulated Comprehensive Income [Roll Forward]
Balance, beginning of period			$ 595,037
Foreign currency translation adjustment, net of tax	$ (8,829)	$ (2,635)	2,276	$ (6,326)
Available-for-sale securities adjustments, net of tax	(48)	0	(48)	0
Change in fair value, net of tax			319	1,088
Reclassification adjustment into earnings, net of tax			(382)	(269)
Balance, end of period	634,181		634,181
Other Comprehensive Income, Tax [Abstract]
Foreign currency translation adjustment, tax			(2,303)	(1,814)
Available-for-sale securities adjustments, tax			0	0
Change in fair value, tax			111	610
Reclassification adjustment into earnings, tax			(133)	(150)
Change in pension and other postretirement liabilities, tax			0	0
Accumulated Other Comprehensive Income (Loss) [Member]
Components of Accumulated Comprehensive Income [Roll Forward]
Balance, beginning of period			3,949	9,556
Balance, end of period	6,114	4,049	6,114	4,049
Foreign Currency Translation [Member]
Components of Accumulated Comprehensive Income [Roll Forward]
Balance, beginning of period			5,239	11,985
Foreign currency translation adjustment, net of tax			2,276	(6,326)
Balance, end of period	7,515	5,659	7,515	5,659
Cash Flow Hedges [Member]
Components of Accumulated Comprehensive Income [Roll Forward]
Balance, beginning of period			46	(817)
Change in fair value, net of tax			319	1,088
Reclassification adjustment into earnings, net of tax			(382)	(269)
Balance, end of period	(17)	2	(17)	2
Pension and Other Postretirement Liabilities [Member]
Components of Accumulated Comprehensive Income [Roll Forward]
Balance, beginning of period			(1,336)	(1,612)
Balance, end of period	(1,336)	$ (1,612)	(1,336)	$ (1,612)
Available-For-Sale Securities
Components of Accumulated Comprehensive Income [Roll Forward]
Balance, beginning of period			0
Available-for-sale securities adjustments, net of tax			(48)
Balance, end of period	$ (48)		$ (48)

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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The amount of net gains or losses on interest rate cash flow hedges reclassified during the period to earnings from accumulated other comprehensive income upon the hedged transaction affecting earnings.

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Amount after tax and reclassification adjustments, of appreciation (loss) in value of unsold available-for-sale securities, attributable to parent entity. Excludes amounts related to other than temporary impairment (OTTI) loss.

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Amount of tax expense (benefit), after reclassification adjustments, of appreciation (loss) in value of unsold available-for-sale securities, attributable to parent entity. Excludes amounts related to other than temporary impairment (OTTI) loss.

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Amount, after reclassification adjustment, of tax (expense) benefit for (increase) decrease in accumulated other comprehensive income for defined benefit plan, attributable to parent.

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