v3.25.2
Note 1 - Summary of Accounting Policies (Details Textual) - USD ($)
$ / shares in Units, $ in Thousands
 12 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2023
Debt Securities, Trading $ 5,000 $ 4,900  
Equity Securities without Readily Determinable Fair Value, Amount   2,000  
Payments to Acquire Debt Securities, Available-for-Sale   $ 2,700  
Common Stock, Par or Stated Value Per Share (in dollars per share) $ 1.5 $ 1.5  
Common Stock, Shares Authorized (in shares) 60,000,000 60,000,000  
Common Stock, Shares, Issued (in shares) 27,984,278 27,984,278  
Common Stock, Shares, Outstanding (in shares) 11,992,116 11,761,700  
Treasury Stock, Common, Shares (in shares) 15,992,162 16,222,578  
Treasury Stock, Shares, Acquired (in shares) 31,308    
Stock Issued During Period, Shares, Acquisitions (in shares) 152,299    
Stock Issued During Period, Shares, Employee Stock Purchase Plans (in shares) 109,425    
Income Tax Expense (Benefit) $ 11,084 $ 21,532 $ 24,796
Effective Income Tax Rate Reconciliation, Percent 16.10% 22.60% 15.10%
Effective Income Tax Rate Reconciliation, Mix of Income in Various Jurisdictions $ 5,700 $ 3,100 $ (4,300)
Effective Income Tax Rate Reconciliation, Tax Credit, Amount 4,600 2,800 14,300
Effective Income Tax Rate Reconciliation, Tax Credit, Foreign, Amount 2,100 700 11,600
Effective Income Tax Rate Reconciliation, Tax Credit, Research, Amount 2,500 2,100 2,700
Effective Income Tax Rate Reconciliation, Officer Compensation, Amount 1,800 3,800  
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Amount 3,000   11,300
Effective Income Tax Reconciliation, Release of Uncertain Tax Position 9,100    
Effective Income Tax Reconciliation, Release of Uncertain Tax Position, Interest 1,200    
Effective Income Tax Rate Reconciliation, Tax Expense (Benefit), Share-Based Payment Arrangement, Amount $ 900 $ (3,800)  
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount     $ 5,000
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares) 0 0 0
Selling, General and Administrative Expenses [Member]      
Advertising Expense $ 2,600 $ 2,400 $ 2,700
Research and Development Expense $ 21,200 20,500 $ 17,200
Revenue Benchmark [Member]      
Concentration Risk, Threshold Percentage 5.00%    
Sanyu Electric Pte Ltd [Member]      
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High   $ 700