STOCKHOLDERS' EQUITY AND EQUITY COMPENSATION (Details) - Summary of stock-based compensation expense (Details) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Stockholders' Equity Note [Abstract]
Pre-tax compensation expense	$ 13,285	$ 10,078	$ 8,090
Tax benefit	(2,115)	(2,036)	(2,836)
Total stock-based compensation expense, net of tax	$ 11,170	$ 8,042	$ 5,254

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
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5047-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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