v3.26.3
Summary of Significant Accounting Policies - Investments in Marketable Securities (Details) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Jun. 30, 2026
Marketable securities      
Investment income, nonoperating $ 8,800 $ 9,500  
Marketable securities, short-term portion 241,500   $ 203,600
Marketable securities, long-term portion $ 95,200   $ 76,200
Marketable Securities, Maturity Date, Start 1 year   1 year
Marketable Securities, Maturity Date, End 2 years   2 years
Amortized Cost $ 336,733   $ 279,805
Allowance for Credit Losses (272)   (222)
Net Carrying Amount 336,461   279,583
Gross Unrealized Losses (1,475)   (528)
Fair Value 334,986   279,055
Equity securities 0   42,300
Sale of publicly held equity securities 35,110    
Realized loss (7,200)    
Net unrealized gain   $ 6,700  
Corporate Bonds      
Marketable securities      
Amortized Cost 145,275   112,160
Allowance for Credit Losses (202)   (160)
Net Carrying Amount 145,073   112,000
Gross Unrealized Losses (902)   (269)
Fair Value 144,171   111,731
U.S. Treasury Notes      
Marketable securities      
Amortized Cost 191,458   141,689
Allowance for Credit Losses (70)   (50)
Net Carrying Amount 191,388   141,639
Gross Unrealized Losses (573)   (259)
Fair Value $ 190,815   141,380
Commercial Paper      
Marketable securities      
Amortized Cost     25,956
Allowance for Credit Losses     (12)
Net Carrying Amount     25,944
Fair Value     $ 25,944