OTHER COMPREHENSIVE INCOME (LOSS) (Details) - Summary of Other Comprehensive Income - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Jun. 30, 2019	Jun. 30, 2018
Other Comprehensive Income (Loss), before Tax [Abstract]
Foreign currency translation adjustments	$ (1,092)			$ (9,136)			$ (3,943)	$ 9,289
Pension and other defined benefit plans	236			376			708	14,996
Cash flow hedges	(199)			118			(306)	864
Total other comprehensive income (loss)	(1,055)			(8,642)			(3,541)	25,149
Other Comprehensive Income (Loss), Tax [Abstract]
Pension and other defined benefit plans	(52)			(129)			(156)	(4,943)
Cash flow hedges	72			(34)			92	(252)
Total other comprehensive income (loss)	20			(163)			(64)	(5,195)
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Foreign currency translation adjustments	(1,092)			(9,136)			(3,943)	9,289
Pension and other defined benefit plans	184			247			552	10,053
Cash flow hedges	(127)			84			(214)	612
Total other comprehensive income (loss), net of taxes	$ (1,035)	$ 2,880	$ (5,450)	$ (8,805)	$ 20,401	$ 8,358	$ (3,605)	$ 19,954

Amount before tax, after reclassification adjustments of other comprehensive income (loss).

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Amount after tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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