GOODWILL AND OTHER INTANGIBLE ASSETS - Changes in carrying amount of goodwill (Details) $ in Thousands	3 Months Ended
	Dec. 31, 2021 USD ($)
Changes in goodwill
Goodwill, Beginning Balance	$ 504,853
Acquisition activity and adjustments	5,900
Foreign currency translation and other	(1,500)
Goodwill, Ending Balance	509,268
USG
Changes in goodwill
Goodwill, Beginning Balance	366,500
Acquisition activity and adjustments	200
Foreign currency translation and other	(1,500)
Goodwill, Ending Balance	365,200
Test
Changes in goodwill
Goodwill, Beginning Balance	34,100
Goodwill, Ending Balance	34,100
A&D
Changes in goodwill
Goodwill, Beginning Balance	104,300
Acquisition activity and adjustments	5,700
Goodwill, Ending Balance	$ 110,000