v3.26.1
Fair Value Measurements (Details) - USD ($)
$ in Thousands
Mar. 31, 2026
Sep. 30, 2025
Assets:    
Cash and cash equivalents $ 537,712 $ 450,739
Short-term investments 7,177 24,788
Liabilities:    
Deferred compensation 14,831 13,707
Contingent future payments related to the acquisition of Remsdaq 2,574 2,344
Rabbi trust assets    
Assets:    
Rabbi trust assets 15,050 13,931
Quoted Prices in Active Markets for Identical Assets (Level 1)    
Assets:    
Cash and cash equivalents 537,712 450,739
Short-term investments 7,177 24,788
Liabilities:    
Deferred compensation 0 0
Contingent future payments related to the acquisition of Remsdaq 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Rabbi trust assets    
Assets:    
Rabbi trust assets 0 0
Significant Other Observable Inputs (Level 2)    
Assets:    
Cash and cash equivalents 0 0
Short-term investments 0 0
Liabilities:    
Deferred compensation 14,831 13,707
Contingent future payments related to the acquisition of Remsdaq 0 0
Significant Other Observable Inputs (Level 2) | Rabbi trust assets    
Assets:    
Rabbi trust assets 15,050 13,931
Significant Unobservable Inputs (Level 3)    
Assets:    
Cash and cash equivalents 0 0
Short-term investments 0 0
Liabilities:    
Deferred compensation 0 0
Contingent future payments related to the acquisition of Remsdaq 2,574 2,344
Significant Unobservable Inputs (Level 3) | Rabbi trust assets    
Assets:    
Rabbi trust assets $ 0 $ 0