v3.26.3
Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis and Categorized using Fair Value Hierarchy (Detail) - Fair Value, Measurements, Recurring - USD ($)
$ in Thousands
Aug. 31, 2026
May 31, 2026
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total available-for-sale debt securities $ 25,307 $ 25,354
Total marketable equity securities 185,242 174,394
Assets (liabilities) at fair value 210,141 194,399
U.S. Treasury and other government    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total available-for-sale debt securities 25,190 25,231
Corporate bonds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total available-for-sale debt securities 117 123
Stocks | Foreign    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total marketable equity securities 389 370
Stocks | Domestic    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total marketable equity securities 5,525 5,213
Mutual funds | Foreign    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total marketable equity securities 52,599 49,082
Mutual funds | Domestic    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total marketable equity securities 126,729 119,729
Contingent consideration liability    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Contingent consideration (408) (5,349)
Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total marketable equity securities 20,033 19,247
Assets (liabilities) at fair value 20,033 19,247
Quoted Prices in Active Markets for Identical Assets (Level 1) | Stocks | Foreign    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total marketable equity securities 389 370
Quoted Prices in Active Markets for Identical Assets (Level 1) | Stocks | Domestic    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total marketable equity securities 5,525 5,213
Quoted Prices in Active Markets for Identical Assets (Level 1) | Mutual funds | Domestic    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total marketable equity securities 14,119 13,664
Significant Other Observable Inputs (Level 2)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total available-for-sale debt securities 25,307 25,354
Total marketable equity securities 165,209 155,147
Assets (liabilities) at fair value 190,516 180,501
Significant Other Observable Inputs (Level 2) | U.S. Treasury and other government    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total available-for-sale debt securities 25,190 25,231
Significant Other Observable Inputs (Level 2) | Corporate bonds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total available-for-sale debt securities 117 123
Significant Other Observable Inputs (Level 2) | Mutual funds | Foreign    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total marketable equity securities 52,599 49,082
Significant Other Observable Inputs (Level 2) | Mutual funds | Domestic    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total marketable equity securities 112,610 106,065
Significant Unobservable Inputs (Level 3)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets (liabilities) at fair value (408) (5,349)
Significant Unobservable Inputs (Level 3) | Contingent consideration liability    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Contingent consideration $ (408) $ (5,349)