OTHER COMPREHENSIVE INCOME (LOSS) (Details) - Summary of Amounts Reclassified from Accumulated Other Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
OCI, Net of Tax [Abstract]
Pension amortization	$ (529)	$ (836)	$ (1,058)	$ (1,672)
Cash flow hedges	(34)	(172)	(40)	(821)
Removal of PPC translation adjustment	(14,866)	0	(14,866)	0
Total gain (loss)	14,303	(1,008)	13,768	(2,493)
Tax benefit (expense)	3,315	(303)	3,313	(748)
Amounts reclassified from accumulated other comprehensive income (loss)	$ 10,988	$ (705)	$ 10,455	$ (1,745)