OTHER COMPREHENSIVE INCOME (LOSS) (Details) - Summary of Other Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
Pre-tax
Foreign currency translation adjustments	$ 8,409	$ 13,683	$ (5,070)	$ 10,334
Pension and other defined benefit plans	836	595	1,672	1,189
Cash flow hedges	(1,428)	(2,355)	844	(3,805)
Total other comprehensive income (loss)	7,817	11,923	(2,554)	7,718
Tax
Pension and other defined benefit plans	(292)	(209)	(584)	(417)
Cash flow hedges	408	706	(241)	1,141
Total other comprehensive income (loss)	116	497	(825)	724
Net of tax
Foreign currency translation adjustments	8,409	13,683	(5,070)	10,334
Pension and other defined benefit plans	544	386	1,088	772
Cash flow hedges	(1,020)	(1,649)	603	(2,664)
Total other comprehensive income (loss), net of taxes	$ 7,933	$ 12,420	$ (3,379)	$ 8,442