Revenue Recognition - Summary of Disaggregated Revenue (Detail) - USD ($) $ in Millions	12 Months Ended
	May 31, 2026	May 31, 2025	May 31, 2024
Disaggregation of Revenue [Line Items]
Total Revenues	$ 870.4	$ 894.7	$ 924.2
Food Safety
Disaggregation of Revenue [Line Items]
Total Revenues	641.1	638.1	655.3
Food Safety \| Natural Toxins & Allergens
Disaggregation of Revenue [Line Items]
Total Revenues	77.5	77.0	82.2
Food Safety \| Bacterial & General Sanitation
Disaggregation of Revenue [Line Items]
Total Revenues	175.4	164.8	171.2
Food Safety \| Indicator Testing & Culture Media
Disaggregation of Revenue [Line Items]
Total Revenues	332.7	312.2	322.0
Food Safety \| Rodenticides, Insecticides & Disinfectants
Disaggregation of Revenue [Line Items]
Total Revenues	18.2	47.0	43.0
Food Safety \| Genomics Services
Disaggregation of Revenue [Line Items]
Total Revenues	24.6	23.4	24.3
Food Safety \| Other
Disaggregation of Revenue [Line Items]
Total Revenues	12.7	13.7	12.6
Animal Safety
Disaggregation of Revenue [Line Items]
Total Revenues	229.3	256.6	268.9
Animal Safety \| Life Sciences
Disaggregation of Revenue [Line Items]
Total Revenues	6.6	6.5	6.5
Animal Safety \| Animal Care & Other
Disaggregation of Revenue [Line Items]
Total Revenues	29.3	34.7	37.0
Animal Safety \| Veterinary Instruments & Disposables
Disaggregation of Revenue [Line Items]
Total Revenues	56.9	61.5	65.8
Animal Safety \| Rodenticides, Insecticides & Disinfectants
Disaggregation of Revenue [Line Items]
Total Revenues	68.9	88.1	88.7
Animal Safety \| Genomics Services
Disaggregation of Revenue [Line Items]
Total Revenues	$ 67.6	$ 65.8	$ 70.8