v3.26.1
Note 10 - Retirement Plans - Fair Value of Plan Assets (Details) - USD ($)
$ in Thousands
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Plan Assets, Amount $ 323,061 $ 293,121 $ 288,949
Defined Benefit Plan, Equity Securities [Member]      
Plan Assets, Amount 70,860 42,767  
Defined Benefit Plan, Equity Securities Held in Common Collective Trusts [Member]      
Plan Assets, Amount 28,859 26,903  
Defined Benefit Plan, Real Estate Held in Common Collective Trusts [Member]      
Plan Assets, Amount 7,505 4,451  
Defined Benefit Plan, Debt Security Held in Common Collective Trusts [Member]      
Plan Assets, Amount 207,304 212,162  
Defined Benefit Plan, Cash and Short-term Investments Held in Common Collective Trusts [Member]      
Plan Assets, Amount [1] 3,457 3,485  
All Other Investments [Member]      
Plan Assets, Amount 5,076 3,353  
Fair Value, Inputs, Level 1 [Member]      
Plan Assets, Amount 70,860 42,767  
Fair Value, Inputs, Level 1 [Member] | Defined Benefit Plan, Equity Securities [Member]      
Plan Assets, Amount 70,860 42,767  
Fair Value, Inputs, Level 1 [Member] | Defined Benefit Plan, Equity Securities Held in Common Collective Trusts [Member]      
Plan Assets, Amount 0 0  
Fair Value, Inputs, Level 1 [Member] | Defined Benefit Plan, Real Estate Held in Common Collective Trusts [Member]      
Plan Assets, Amount 0 0  
Fair Value, Inputs, Level 1 [Member] | Defined Benefit Plan, Debt Security Held in Common Collective Trusts [Member]      
Plan Assets, Amount 0 0  
Fair Value, Inputs, Level 1 [Member] | Defined Benefit Plan, Cash and Short-term Investments Held in Common Collective Trusts [Member]      
Plan Assets, Amount [1] 0 0  
Fair Value, Inputs, Level 1 [Member] | All Other Investments [Member]      
Plan Assets, Amount 0 0  
Fair Value, Inputs, Level 2 and Level 3 [Member]      
Plan Assets, Amount 0 0  
Fair Value, Inputs, Level 2 and Level 3 [Member] | Defined Benefit Plan, Equity Securities [Member]      
Plan Assets, Amount 0 0  
Fair Value, Inputs, Level 2 and Level 3 [Member] | Defined Benefit Plan, Equity Securities Held in Common Collective Trusts [Member]      
Plan Assets, Amount 0 0  
Fair Value, Inputs, Level 2 and Level 3 [Member] | Defined Benefit Plan, Real Estate Held in Common Collective Trusts [Member]      
Plan Assets, Amount 0 0  
Fair Value, Inputs, Level 2 and Level 3 [Member] | Defined Benefit Plan, Debt Security Held in Common Collective Trusts [Member]      
Plan Assets, Amount 0 0  
Fair Value, Inputs, Level 2 and Level 3 [Member] | Defined Benefit Plan, Cash and Short-term Investments Held in Common Collective Trusts [Member]      
Plan Assets, Amount [1] 0 0  
Fair Value, Inputs, Level 2 and Level 3 [Member] | All Other Investments [Member]      
Plan Assets, Amount 0 0  
Fair Value, Inputs, Level 1, Level 2, and Level 3 [Member]      
Plan Assets, Amount 70,860 42,767  
Fair Value, Inputs, Level 1, Level 2, and Level 3 [Member] | Defined Benefit Plan, Equity Securities [Member]      
Plan Assets, Amount 70,860 42,767  
Fair Value, Inputs, Level 1, Level 2, and Level 3 [Member] | Defined Benefit Plan, Equity Securities Held in Common Collective Trusts [Member]      
Plan Assets, Amount 0 0  
Fair Value, Inputs, Level 1, Level 2, and Level 3 [Member] | Defined Benefit Plan, Real Estate Held in Common Collective Trusts [Member]      
Plan Assets, Amount 0 0  
Fair Value, Inputs, Level 1, Level 2, and Level 3 [Member] | Defined Benefit Plan, Debt Security Held in Common Collective Trusts [Member]      
Plan Assets, Amount 0 0  
Fair Value, Inputs, Level 1, Level 2, and Level 3 [Member] | Defined Benefit Plan, Cash and Short-term Investments Held in Common Collective Trusts [Member]      
Plan Assets, Amount [1] 0 0  
Fair Value, Inputs, Level 1, Level 2, and Level 3 [Member] | All Other Investments [Member]      
Plan Assets, Amount 0 0  
Fair Value Measured at Net Asset Value Per Share [Member]      
Plan Assets, Amount [2] 252,201 250,354  
Fair Value Measured at Net Asset Value Per Share [Member] | Defined Benefit Plan, Equity Securities [Member]      
Plan Assets, Amount [2] 0 0  
Fair Value Measured at Net Asset Value Per Share [Member] | Defined Benefit Plan, Equity Securities Held in Common Collective Trusts [Member]      
Plan Assets, Amount [2] 28,859 26,903  
Fair Value Measured at Net Asset Value Per Share [Member] | Defined Benefit Plan, Real Estate Held in Common Collective Trusts [Member]      
Plan Assets, Amount [2] 7,505 4,451  
Fair Value Measured at Net Asset Value Per Share [Member] | Defined Benefit Plan, Debt Security Held in Common Collective Trusts [Member]      
Plan Assets, Amount [2] 207,304 212,162  
Fair Value Measured at Net Asset Value Per Share [Member] | Defined Benefit Plan, Cash and Short-term Investments Held in Common Collective Trusts [Member]      
Plan Assets, Amount [1],[2] 3,457 3,485  
Fair Value Measured at Net Asset Value Per Share [Member] | All Other Investments [Member]      
Plan Assets, Amount [2] $ 5,076 $ 3,353  
[1] The cash/short term investments consist of a money market fund that holds individual, high quality, short duration fixed income investments, however the fund does not trade on public markets. The Company elected to consistently apply the practical expedient to all investments within common/collective trusts, and therefore, the fair value of this fund is measured at net asset value per share.
[2] Certain investments that are measured at fair value using the net asset value (“NAV”) per share (or its equivalent) practical expedient have not been categorized in the fair value hierarchy but are included to reconcile to the amounts presented in the benefit obligations and funded status table.