SEGMENT AND GEOGRAPHIC INFORMATION - Operating Segments Revenue and Operating Income (Loss) (Details) $ in Thousands	12 Months Ended
	Sep. 30, 2022 USD ($) segment	Sep. 30, 2021 USD ($)
SEGMENT INFORMATION
Number of segments | segment	2
Revenue	$ 547,656	$ 89,605
Operating Income (Loss)	(263,452)	(5,618)
Interest expense	(29,704)	(1,683)
Other (expense) income	(59,293)	13,420
(Loss) income before income taxes	(352,449)	6,119
Service
SEGMENT INFORMATION
Revenue	202,978	85,832
Product
SEGMENT INFORMATION
Revenue	344,678	3,773
Intersegment
SEGMENT INFORMATION
Revenue	7,250
Discovery and Safety Assessment Segment (DSA)
SEGMENT INFORMATION
Operating Income (Loss)	22,330
Discovery and Safety Assessment Segment (DSA) | Service
SEGMENT INFORMATION
Revenue	161,113
Discovery and Safety Assessment Segment (DSA) | Product
SEGMENT INFORMATION
Revenue	4,176
Research Models And Services Segment (RMS)
SEGMENT INFORMATION
Operating Income (Loss)	(189,346)
Research Models And Services Segment (RMS) | Service
SEGMENT INFORMATION
Revenue	41,865
Research Models And Services Segment (RMS) | Product
SEGMENT INFORMATION
Revenue	340,502
Services Segment
SEGMENT INFORMATION
Revenue		85,832
Operating Income (Loss)		13,986
Products Segment
SEGMENT INFORMATION
Revenue		3,773
Operating Income (Loss)		202
Unallocated Corporate Segment
SEGMENT INFORMATION
Operating Income (Loss)	$ (96,436)	$ (19,806)