Revenue Recognition - Summary of Disaggregated Revenue (Detail) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2025	May 31, 2024	May 31, 2023
Disaggregation of Revenue [Line Items]
Total Revenues	$ 894,661	$ 924,222	$ 822,447
Food Safety
Disaggregation of Revenue [Line Items]
Total Revenues	638,140	655,341	546,797
Food Safety \| Natural Toxins & Allergens
Disaggregation of Revenue [Line Items]
Total Revenues	77,058	82,240	82,567
Food Safety \| Bacterial & General Sanitation
Disaggregation of Revenue [Line Items]
Total Revenues	164,777	171,217	134,934
Food Safety \| Indicator Testing, Culture Media And Other
Disaggregation of Revenue [Line Items]
Total Revenues	325,915	334,636	267,178
Food Safety \| Rodenticides, Insecticides & Disinfectants
Disaggregation of Revenue [Line Items]
Total Revenues	46,971	42,965	39,655
Food Safety \| Genomics Services
Disaggregation of Revenue [Line Items]
Total Revenues	23,419	24,283	22,463
Animal Safety
Disaggregation of Revenue [Line Items]
Total Revenues	256,521	268,881	275,650
Animal Safety \| Life Sciences
Disaggregation of Revenue [Line Items]
Total Revenues	6,500	6,515	6,254
Animal Safety \| Animal Care & Other
Disaggregation of Revenue [Line Items]
Total Revenues	34,654	36,978	39,068
Animal Safety \| Veterinary Instruments & Disposables
Disaggregation of Revenue [Line Items]
Total Revenues	61,468	65,848	63,843
Animal Safety \| Rodenticides, Insecticides & Disinfectants
Disaggregation of Revenue [Line Items]
Total Revenues	88,063	88,732	87,423
Animal Safety \| Genomics Services
Disaggregation of Revenue [Line Items]
Total Revenues	$ 65,836	$ 70,808	$ 79,062