BUSINESS COMBINATIONS (Details) - USD ($) $ in Thousands		12 Months Ended
	Jun. 02, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Business Combinations
Amortization period of developed technology		15 years
Amortization		$ 1,100
Expected annual amortization		3,400
Fair value of assets acquired
Goodwill		51,705	$ 4,718	$ 4,718
Fair value of liabilities assumed
Contingent earnout liability		14,879
(Level 3)
Fair value of liabilities assumed
Contingent earnout liability		14,879
MOTIVE Merger
Business Combinations
Payment for business acquisition	$ 74,275
Future potential earnout payments	25,000
Escrow deposit	$ 9,400
Percentage of escrow to be released to seller on each of twelve and eight month anniversaries	50.00%
Revenues		3,300
Net loss		(2,200)
Purchase Price
Cash consideration	$ 74,275
Long-term contingent earnout liability (Other noncurrent liabilities)	14,509
Total cash consideration given	88,784
Fair value of assets acquired
Current assets	4,425
Property, plant and equipment	300
Intangible asset - developed technology (Intangible assets, net of amortization)	51,000
Goodwill	46,987
Total assets acquired	102,712
Fair value of liabilities assumed
Current liabilities	25
Deferred income taxes	13,903
Total liabilities acquired	13,928
Fair value of total assets and liabilities acquired	$ 88,784
Proforma financial information:
After tax transaction cost adjusted for proforma financial information		2,100
Revenues		1,807,950	1,626,305
Net loss		(127,093)	$ (59,776)
MOTIVE Merger | Developed technology
Business Combinations
Amortization period of developed technology	15 years
Amortization		1,100
Expected annual amortization	$ 3,400
MOTIVE Merger | General and Administrative
Business Combinations
Business acquisition transaction cost		3,200
MOTIVE Merger | (Level 3)
Fair value of liabilities assumed
Contingent earnout liability	$ 14,500	$ 14,900