v3.26.1
Reclassifications out of Accumulated Other Comprehensive Loss (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance $ 2,475,428 $ 2,466,287 $ 2,696,184 $ 2,370,410
Ending balance 2,399,405 2,698,605 2,399,405 2,698,605
Accumulated Other Comprehensive Loss        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance (896,242) (943,127) (893,027) (882,671)
Other comprehensive (loss) income before reclassification 13,700 70,100 12,400 13,800
Amounts reclassified from accumulated other comprehensive (loss) income (800) (1,900) (2,700) (6,000)
Ending balance (883,249) (874,861) (883,249) (874,861)
Accumulated Other Comprehensive Loss | Adjusted for rounding        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Ending balance (883,300)   (883,300)  
Pension Related Adjustments        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance (245,300) (243,600) (251,400) (252,000)
Other comprehensive (loss) income before reclassification (2,600) (13,700) 2,200 (6,200)
Amounts reclassified from accumulated other comprehensive (loss) income 600 400 1,900 1,300
Ending balance (247,300) (256,900) (247,300) (256,900)
Foreign Currency Translation Adjustments        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance (662,000) (717,300) (652,400) (646,500)
Other comprehensive (loss) income before reclassification 13,900 85,300 4,300 14,500
Amounts reclassified from accumulated other comprehensive (loss) income 0 0 0 0
Ending balance (648,100) (632,000) (648,100) (632,000)
Gain/(Loss) on Derivative Instruments        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning balance 11,100 17,800 10,800 15,800
Other comprehensive (loss) income before reclassification 2,400 (1,500) 5,900 5,500
Amounts reclassified from accumulated other comprehensive (loss) income (1,400) (2,300) (4,600) (7,300)
Ending balance $ 12,100 $ 14,000 $ 12,100 $ 14,000