Pension Benefit Obligations - Schedule of Amounts Recognized In the Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Amounts recognized in the consolidated balance sheets:
Pension benefit obligations	$ (133,193)	$ (172,360)
U.S.
Amounts recognized in the consolidated balance sheets:
Other non-current assets	0	0	$ 0
Accrued expenses and other current liabilities	(8,500)	(8,300)	(8,400)
Pension benefit obligations	(63,500)	(69,600)	(74,000)
Net amount recognized at end of year	(72,000)	(77,900)	(82,400)
Int’l
Amounts recognized in the consolidated balance sheets:
Other non-current assets	52,300	46,600	38,700
Accrued expenses and other current liabilities	0	0	0
Pension benefit obligations	(69,700)	(102,700)	(121,600)
Net amount recognized at end of year	$ (17,400)	$ (56,100)	$ (82,900)