v3.26.1
Fair Value Measurements - Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - USD ($)
$ in Thousands
Mar. 31, 2026
Sep. 30, 2025
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Financial instruments net assets $ 3,413 $ 9,897
Total debt and equity securities 119,566 114,938
Total assets 122,979 124,835
Financial instruments net liability 805 6,485
Registered investment companies    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Equity securities 26,761 26,463
Bond mutual funds    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Equity securities 42,739 42,106
Bonds    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Bonds 48,464 42,754
Money market funds    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Equity securities 1,602 3,615
Quoted Prices in Active Markets (Level 1)    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Financial instruments gross assets 0 0
Total debt and equity securities 69,500 68,569
Total assets 69,500 68,569
Financial instruments gross liability 0 0
Quoted Prices in Active Markets (Level 1) | Registered investment companies    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Equity securities 26,761 26,463
Quoted Prices in Active Markets (Level 1) | Bond mutual funds    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Equity securities 42,739 42,106
Quoted Prices in Active Markets (Level 1) | Bonds    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Bonds 0 0
Quoted Prices in Active Markets (Level 1) | Money market funds    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Equity securities 0 0
Significant Other Observable Inputs (Level 2)    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Financial instruments gross assets 3,413 9,897
Total debt and equity securities 50,066 46,369
Total assets 53,479 56,266
Financial instruments gross liability 805 6,485
Significant Other Observable Inputs (Level 2) | Registered investment companies    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Equity securities 0 0
Significant Other Observable Inputs (Level 2) | Bond mutual funds    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Equity securities 0 0
Significant Other Observable Inputs (Level 2) | Bonds    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Bonds 48,464 42,754
Significant Other Observable Inputs (Level 2) | Money market funds    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Equity securities 1,602 3,615
Significant Other Unobservable Inputs (Level 3)    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Financial instruments gross assets 0 0
Total debt and equity securities 0 0
Total assets 0 0
Financial instruments gross liability 0 0
Significant Other Unobservable Inputs (Level 3) | Registered investment companies    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Equity securities 0 0
Significant Other Unobservable Inputs (Level 3) | Bond mutual funds    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Equity securities 0 0
Significant Other Unobservable Inputs (Level 3) | Bonds    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Bonds 0 0
Significant Other Unobservable Inputs (Level 3) | Money market funds    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Equity securities $ 0 $ 0