Reclassifications out of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Accumulated balances
Balance at the beginning of the period	$ (900,377)	$ (918,700)
Other comprehensive income (loss) before reclassification	(2,200)	38,000
Amounts reclassified from accumulated other comprehensive (loss) income	3,400	3,900
Balance at the end of the period	(899,172)	(876,800)
Pension Related Adjustments
Accumulated balances
Balance at the beginning of the period	(316,200)	(342,800)
Other comprehensive income (loss) before reclassification	300	(13,700)
Amounts reclassified from accumulated other comprehensive (loss) income	2,500	3,000
Balance at the end of the period	(313,400)	(353,500)
Foreign Currency Translation Adjustments
Accumulated balances
Balance at the beginning of the period	(580,100)	(567,300)
Other comprehensive income (loss) before reclassification	(5,200)	51,700
Balance at the end of the period	(585,300)	(515,600)
(Loss)/Gain on Derivative Instruments
Accumulated balances
Balance at the beginning of the period	(4,100)	(8,600)
Other comprehensive income (loss) before reclassification	2,700
Amounts reclassified from accumulated other comprehensive (loss) income	900	900
Balance at the end of the period	$ (500)	$ (7,700)