Pension Benefit Obligations - Balance Sheet Recognition (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Amounts recognized in the consolidated balance sheets:
Pension benefit obligations	$ (505,834)	$ (412,604)
United States
Amounts recognized in the consolidated balance sheets:
Other non-current assets	2,700	2,500	$ 2,300
Accrued expenses and other current liabilities	(9,100)	(9,500)	(10,100)
Pension benefit obligations	(235,000)	(170,600)	(204,800)
Net amount recognized in the balance sheet	(241,400)	(177,600)	(212,600)
International
Amounts recognized in the consolidated balance sheets:
Other non-current assets	28,300	19,100	13,900
Pension benefit obligations	(270,800)	(242,000)	(354,300)
Net amount recognized in the balance sheet	$ (242,500)	$ (222,900)	$ (340,400)

Amount of asset (liability), recognized in statement of financial position, for defined benefit pension and other postretirement plans.

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Amount of asset, recognized in statement of financial position, for overfunded defined benefit pension and other postretirement plans.

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Amount of liability, recognized in statement of financial position, for defined benefit pension and other postretirement plans, classified as current.

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Amount of liability, recognized in statement of financial position, for defined benefit pension and other postretirement plans, classified as noncurrent.

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