Segment Information and Geographic Data - Schedule of Segment Information (Detail) - USD ($) $ in Thousands		3 Months Ended				6 Months Ended
		Nov. 30, 2023		Nov. 30, 2022		Nov. 30, 2023		Nov. 30, 2022		May 31, 2023
Segment Reporting Information [Line Items]
Total revenues to external customers		$ 229,629		$ 230,033		$ 458,616		$ 362,382
Operating income (loss)		14,465		(7,656)		33,600		(1,594)
Total Assets		4,602,415		4,563,242		4,602,415		4,563,242		$ 4,554,432
Operating Segments | Food Safety
Segment Reporting Information [Line Items]
Total revenues to external customers		164,403		161,343		330,681		225,986
Operating income (loss)		24,329		21,446		46,570		30,042
Total Assets		4,029,108		3,955,488		4,029,108		3,955,488
Operating Segments | Animal Safety
Segment Reporting Information [Line Items]
Total revenues to external customers		65,226		68,690		127,935		136,396
Operating income (loss)		7,739		12,806		16,095		24,687
Total Assets		341,919		329,177		341,919		329,177
Product Revenues
Segment Reporting Information [Line Items]
Total revenues to external customers		203,869		203,317		408,270		310,109
Product Revenues | Operating Segments | Food Safety
Segment Reporting Information [Line Items]
Total revenues to external customers		156,317		154,223		315,264		212,013
Product Revenues | Operating Segments | Animal Safety
Segment Reporting Information [Line Items]
Total revenues to external customers		47,552		49,094		93,006		98,096
Service Revenues
Segment Reporting Information [Line Items]
Total revenues to external customers		25,760		26,716		50,346		52,273
Service Revenues | Operating Segments | Food Safety
Segment Reporting Information [Line Items]
Total revenues to external customers		8,086		7,120		15,417		13,973
Service Revenues | Operating Segments | Animal Safety
Segment Reporting Information [Line Items]
Total revenues to external customers		17,674		19,596		34,929		38,300
Corporate and Eliminations | Operating Segments
Segment Reporting Information [Line Items]
Total revenues to external customers		0	[1]	0	[1]	0	[2]	0	[2]
Operating income (loss)		(17,603)	[1]	(41,908)	[1]	(29,065)	[2]	(56,323)	[2]
Total Assets	[1]	231,388		278,577		231,388		278,577
Corporate and Eliminations | Product Revenues | Operating Segments
Segment Reporting Information [Line Items]
Total revenues to external customers		0	[1]	0	[1]	0	[2]	0	[2]
Corporate and Eliminations | Service Revenues | Operating Segments
Segment Reporting Information [Line Items]
Total revenues to external customers		$ 0	[1]	$ 0	[1]	$ 0	[2]	$ 0	[2]

[1] Includes corporate assets, consisting principally of cash and cash equivalents, marketable securities, current and deferred tax accounts and overhead expenses not allocated to specific business segments. Also includes the elimination of intersegment transactions.

[2] Includes the elimination of intersegment transactions.