SEGMENT AND GEOGRAPHIC INFORMATION - Operating Segments Revenue and Operating Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Sep. 30, 2022
SEGMENT INFORMATION
Revenue	$ 157,468	$ 172,666	$ 431,685	$ 397,190	$ 547,656
Operating Income (Loss)	8,783	4,787	(83,920)	(20,986)
Interest expense	(10,786)	(8,441)	(31,751)	(20,816)
Other (expense) income	(12)	440	(1,345)	(57,426)
Loss before income taxes	(2,015)	(3,214)	(117,016)	(99,228)
Depreciation and amortization	13,864	16,001	40,117	31,867
Capital expenditures	4,484	16,073	21,324	31,275
Unallocated Corporate
SEGMENT INFORMATION
Operating Income (Loss)	(17,285)	(20,286)	(55,737)	(78,495)
Service
SEGMENT INFORMATION
Revenue	56,295	60,119	165,095	147,879
Product
SEGMENT INFORMATION
Revenue	101,173	112,547	266,590	249,311
Discovery and Safety Assessment Segment
SEGMENT INFORMATION
Depreciation and amortization	4,235	3,438	11,826	9,396
Capital expenditures	2,403	7,614	9,667	14,031
Discovery and Safety Assessment Segment | Operating Segments
SEGMENT INFORMATION
Operating Income (Loss)	4,182	13,171	8,478	22,965
Discovery and Safety Assessment Segment | Service
SEGMENT INFORMATION
Revenue	45,197	48,217	131,313	118,154
Discovery and Safety Assessment Segment | Product
SEGMENT INFORMATION
Revenue	1,561	1,007	3,561	2,949
Research Models And Services Segment
SEGMENT INFORMATION
Depreciation and amortization	9,629	12,563	28,291	22,471
Capital expenditures	2,081	8,459	11,657	17,244
Research Models And Services Segment | Operating Segments
SEGMENT INFORMATION
Operating Income (Loss)	21,886	11,902	(36,661)	34,544
Research Models And Services Segment | Service
SEGMENT INFORMATION
Revenue	11,098	11,902	33,782	29,725
Research Models And Services Segment | Product
SEGMENT INFORMATION
Revenue	$ 99,612	$ 111,540	$ 263,029	$ 246,362