v3.25.1
Note 9 - Retirement Plans (Details Textual) - USD ($)
$ in Thousands
 12 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Mar. 31, 2023
Defined Contribution Plan, Employer Discretionary Contribution Amount $ 0 $ 0  
Increase Decrease In Unfunded status (23,300)    
Defined Benefit Plan, Plan Assets, Period Increase (Decrease) (19,100)    
Defined Benefit Plan, Benefit Obligation, Period Increase (Decrease) 4,200    
Defined Benefit Plan, Accumulated Benefit Obligation 203,800 219,300  
Defined Benefit Plan, Plan Assets, Amount 293,121 288,949 $ 294,342
Defined Benefit Plan, Benefit Obligation, Benefits Paid $ 21,375 $ 10,750  
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage 100.00%    
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-Term Rate of Return on Plan Assets 6.55% 6.15% 5.00%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Change Due to Subsequent Interim Measurement, Weighted-Average Expected Long-Term Rate of Return on Plan Assets 6.95%    
Defined Benefit Plan, Benefit Obligation $ 217,388 $ 236,507 $ 235,038
Unfunded Deferred Compensation Plan [Member]      
Defined Benefit Plan, Benefit Obligation 3,400 2,500  
Employees’ Savings 401(k) Plan [Member]      
Defined Contribution Plan, Employer Discretionary Contribution Amount $ 2,800 $ 2,500 $ 1,500
Diversified Mix of Return-seeking Investments [Member]      
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage 30.00%    
Fixed Income Investment [Member]      
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage 70.00%    
Lump Sum Payout [Member]      
Defined Benefit Plan, Benefit Obligation, Benefits Paid $ 10,200