SHARE-BASED COMPENSATION PLANS - Share-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 4,234	$ 3,538	$ 8,997	$ 11,708
Tax benefit	(833)	(761)	(1,771)	(2,452)
Total share-based compensation expense, net of tax	3,401	2,777	7,226	9,256
Cost of sales
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	617	574	1,529	1,629
Research, development and technical
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	403	442	1,207	1,343
Selling, general and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 3,214	$ 2,522	$ 6,261	$ 8,736

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
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