SHARE-BASED COMPENSATION PLANS - Share-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 3,194	$ 3,340	$ 12,191	$ 15,048
Tax benefit	(609)	(670)	(2,380)	(3,121)
Total share-based compensation expense, net of tax	2,585	2,670	9,811	11,927
Cost of sales
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	625	540	2,154	2,169
Research, development and technical
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	411	390	1,618	1,733
Selling, general and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 2,158	$ 2,410	$ 8,419	$ 11,146

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
-Section 50
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