OTHER COMPREHENSIVE INCOME (LOSS) (Details) - Summary of Other Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Other Comprehensive Income (Loss), before Tax [Abstract]
Foreign currency translation adjustments	$ (9,136)	$ 6,414	$ 9,289		$ 1,344
Pension and other defined benefit plans	376	836	14,996		2,508
Cash flow hedges	118	277	864		1,121
Total other comprehensive income (loss)	(8,642)	7,527	25,149		4,973
Other Comprehensive Income (Loss), Tax [Abstract]
Pension and other defined benefit plans	(129)	(292)	(4,943)		(876)
Cash flow hedges	(34)	(79)	(252)		(320)
Total other comprehensive income (loss)	(163)	(371)	(5,195)		(1,196)
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Foreign currency translation adjustments	(9,136)	6,414	9,289	$ 1,344	1,344
Pension and other defined benefit plans	247	544	10,053	1,632	1,632
Cash flow hedges	84	198	612		801
Total other comprehensive income (loss), net of taxes	$ (8,805)	$ 7,156	$ 19,954	$ 3,777	$ 3,777