Goodwill and Other Identifiable Intangible Assets, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Sep. 30, 2017
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 110,697	$ 86,308
Accumulated amortization	(76,228)	(74,508)
Net	34,469	11,800
Purchased and Core Technology
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	55,296	51,292
Accumulated amortization	(46,841)	(46,304)
Net	8,455	4,988
License Agreements
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	18	18
Accumulated amortization	(17)	(17)
Net	1	1
Patents and Trademarks
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	14,553	12,484
Accumulated amortization	(11,505)	(11,280)
Net	3,048	1,204
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	40,230	21,914
Accumulated amortization	(17,745)	(16,817)
Net	22,485	5,097
Non-compete Agreements
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	600	600
Accumulated amortization	(120)	(90)
Net	$ 480	$ 510