SEGMENT INFORMATION - Operating Segments Revenue and Operating Income (Loss) (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($) segment	Jun. 30, 2021 USD ($)	Sep. 30, 2021 USD ($)
SEGMENT INFORMATION
Number of segments | segment			2
Revenue	$ 172,666	$ 22,892	$ 397,190	$ 59,529
Operating Income (Loss)	4,787	(1,703)	(20,986)	(2,210)
Interest expense	(8,441)	(449)	(20,816)	(1,163)
Other income (expense)	440	1	(57,426)	180
Loss before income taxes	(3,214)	(2,151)	(99,228)	(3,193)
Assets	1,167,778		1,167,778		$ 321,856
United States
SEGMENT INFORMATION
Revenue	150,540	22,892	340,875	59,529
Netherlands
SEGMENT INFORMATION
Revenue	12,894	0	31,549	0
Other.
SEGMENT INFORMATION
Revenue	9,232	0	24,766	0
Intersegment
SEGMENT INFORMATION
Revenue	2,257		4,574
Discovery and Safety Assessment Segment (DSA)
SEGMENT INFORMATION
Revenue	49,224	22,892	121,103	59,529
Operating Income (Loss)	13,171	3,929	22,965	11,144
Assets	274,570		274,570		321,856
Research Models And Services Segment (RMS)
SEGMENT INFORMATION
Revenue	123,442	0	276,087	0
Operating Income (Loss)	11,902	0	34,544	0
Assets	893,208		893,208		$ 0
Unallocated Corporate Segment
SEGMENT INFORMATION
Operating Income (Loss)	$ (20,286)	$ (5,632)	$ (78,495)	$ (13,354)