CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net (loss) income	$ (68,577)	$ 142,828	$ 39,215
Foreign Currency Transaction and Translation Adjustment:
Foreign currency translation adjustment	2,377	19,642	(7,957)
Income tax benefit (expense)	140	(356)	(591)
Total foreign currency translation adjustment, net of tax	2,517	19,286	(8,548)
Unrealized gain (loss) on cash flow hedges:
Amount of Gain (Loss) Recognized in Other Comprehensive Income (Loss)	7,184	(23,161)	(23,667)
Reclassification adjustment into earnings	14,122	9,360	(524)
Income tax (expense) benefit	(4,765)	3,090	5,411
Total unrealized gain (loss) on cash flow hedges, net of tax	16,541	(10,711)	(18,780)
Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent:
Pension and other postretirement	(211)	891	(479)
Income tax expense	48	156	30
Total pension and other postretirement, net of tax	(163)	1,047	(449)
Other comprehensive income (loss), net of tax	18,895	9,622	(27,777)
Comprehensive (loss) income	$ (49,682)	$ 152,450	$ 11,438