v3.26.3
Segment Information and Geographic Data - Segment Information (Detail) - USD ($)
$ in Millions
 3 Months Ended
Aug. 31, 2026
Aug. 31, 2025
May 31, 2026
Segment Reporting Information [Line Items]      
Operating Expenses $ 107.3 $ 111.1  
Segment Operating Income (1.8) (16.1)  
Total Assets 3,303.2 3,378.1 $ 3,346.0
Depreciation and Amortization 29.1 29.1  
Corporate Interest Expense 13.8 15.5  
Intersegment Revenue      
Segment Reporting Information [Line Items]      
Total Revenues (8.5) (8.1)  
Intersegment Revenue | Food Safety      
Segment Reporting Information [Line Items]      
Total Revenues (6.5) (6.4)  
Intersegment Revenue | Animal Safety      
Segment Reporting Information [Line Items]      
Total Revenues (2.0) (1.7)  
Operating Segments      
Segment Reporting Information [Line Items]      
Total Revenues 231.3 217.3  
Revenue from External Customers 222.8 209.2  
Net Cost of Revenues 117.3 114.2  
Operating Expenses 81.7 83.3  
Segment Operating Income 23.8 11.7  
Total Assets 3,131.2 3,239.2  
Depreciation and Amortization 29.1 29.1  
Expenditures for Long-lived Assets 8.2 24.0  
Corporate Interest Expense 14.4 16.4  
Operating Segments | Food Safety      
Segment Reporting Information [Line Items]      
Total Revenues 169.7 158.5  
Revenue from External Customers 163.2 152.1  
Net Cost of Revenues 80.0 76.5  
Operating Expenses 66.9 68.4  
Segment Operating Income 16.3 7.2  
Total Assets 2,851.6 2,947.3  
Depreciation and Amortization 26.7 25.9  
Expenditures for Long-lived Assets 7.1 23.4  
Operating Segments | Animal Safety      
Segment Reporting Information [Line Items]      
Total Revenues 61.6 58.8  
Revenue from External Customers 59.6 57.1  
Net Cost of Revenues 37.3 37.7  
Operating Expenses 14.8 14.9  
Segment Operating Income 7.5 4.5  
Total Assets 279.6 291.9  
Depreciation and Amortization 2.4 3.2  
Expenditures for Long-lived Assets 1.1 0.6  
Corporate Assets      
Segment Reporting Information [Line Items]      
Total Assets 172.0 138.9  
Corporate Expense and Eliminations | Operating Segments      
Segment Reporting Information [Line Items]      
Segment Operating Income [1] $ 25.6 $ 27.8  
[1] Includes corporate overhead expenses not allocated to specific business segments, and excludes intersegment transactions.