Annual report [Section 13 and 15(d), not S-K Item 405]

Fair Value Measurements - Schedule of Changes in Accumulated Other Comprehensive Loss by Category (Details)

v3.25.3
Fair Value Measurements - Schedule of Changes in Accumulated Other Comprehensive Loss by Category (Details) - USD ($)
$ in Thousands
 12 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2023
Increase (Decrease) in Shareholders' Equity      
Beginning balance $ 1,842,815 $ 1,667,835 $ 1,549,371
Net current period other comprehensive income/(loss) 14,593 (4,845) 6,346
Ending balance 1,674,035 1,842,815 1,667,835
Foreign currency translation adjustment      
Increase (Decrease) in Shareholders' Equity      
Beginning balance (39,225) (50,484) (57,109)
Other comprehensive income/(loss) before reclassifications (2,753) 11,126 6,509
Amounts reclassified from accumulated other comprehensive income/(loss) 21,272 133 116
Net current period other comprehensive income/(loss) 18,519 11,259 6,625
Ending balance (20,706) (39,225) (50,484)
Net unrealized gain on derivatives, net of tax      
Increase (Decrease) in Shareholders' Equity      
Beginning balance 6,765 22,869 23,148
Other comprehensive income/(loss) before reclassifications 4,561 (3,681) 8,558
Amounts reclassified from accumulated other comprehensive income/(loss) (8,487) (12,423) (8,837)
Net current period other comprehensive income/(loss) (3,926) (16,104) (279)
Ending balance 2,839 6,765 22,869
Total      
Increase (Decrease) in Shareholders' Equity      
Beginning balance (32,460) (27,615) (33,961)
Other comprehensive income/(loss) before reclassifications 1,808 7,445 15,067
Amounts reclassified from accumulated other comprehensive income/(loss) 12,785 (12,290) (8,721)
Net current period other comprehensive income/(loss) 14,593 (4,845) 6,346
Ending balance $ (17,867) $ (32,460) $ (27,615)