SEGMENT AND GEOGRAPHIC INFORMATION - Operating Segments Revenue and Operating Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
SEGMENT INFORMATION
Revenue	$ 130,683	$ 105,786	$ 374,882	$ 360,322
Operating Income (Loss)	(5,675)	(20,752)	(24,120)	(73,239)
Interest expense, net	(13,606)	(12,116)	(40,890)	(34,568)
Other income (expense)	519	(82)	464	1,092
Loss before income taxes	(18,762)	(32,950)	(64,546)	(106,715)
Depreciation and amortization	13,985	14,119	41,988	42,524
Capital expenditures	4,006	4,421	13,938	17,015
Unallocated Corporate
SEGMENT INFORMATION
Operating Income (Loss)	(14,202)	(15,630)	(44,784)	(47,037)
Depreciation and amortization	176	230	492	483
Service
SEGMENT INFORMATION
Revenue	59,579	54,364	169,264	165,188
Product
SEGMENT INFORMATION
Revenue	71,104	51,422	205,618	195,134
Discovery and Safety Assessment Segment
SEGMENT INFORMATION
Capital expenditures	549	1,390	2,030	4,594
Discovery and Safety Assessment Segment | Operating Segments
SEGMENT INFORMATION
Operating Income (Loss)	2,149	2,325	4,039	6,771
Depreciation and amortization	4,444	4,488	13,543	13,260
Discovery and Safety Assessment Segment | Service
SEGMENT INFORMATION
Revenue	46,895	43,086	132,834	131,951
Discovery and Safety Assessment Segment | Product
SEGMENT INFORMATION
Revenue	1,255	1,133	3,470	3,597
Research Models And Services Segment
SEGMENT INFORMATION
Capital expenditures	3,457	3,031	11,908	12,421
Research Models And Services Segment | Operating Segments
SEGMENT INFORMATION
Operating Income (Loss)	6,378	(7,447)	16,625	(32,973)
Depreciation and amortization	9,365	9,401	27,953	28,781
Research Models And Services Segment | Service
SEGMENT INFORMATION
Revenue	12,684	11,278	36,430	33,237
Research Models And Services Segment | Product
SEGMENT INFORMATION
Revenue	$ 69,849	$ 50,289	$ 202,148	$ 191,537