Goodwill and other Identifiable Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 122,910	$ 86,308
Accumulated amortization	(83,590)	(74,508)
Net	39,320	11,800
Purchased and Core Technology
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	58,102	51,292
Accumulated amortization	(48,693)	(46,304)
Net	9,409	4,988
License Agreements
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	102	18
Accumulated amortization	(46)	(17)
Net	56	1
Patents and Trademarks
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	15,701	12,484
Accumulated amortization	(12,242)	(11,280)
Net	3,459	1,204
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	46,605	21,914
Accumulated amortization	(21,049)	(16,817)
Net	25,556	5,097
Non-compete Agreements
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	600	600
Accumulated amortization	(210)	(90)
Net	390	510
Order backlog
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,800	0
Accumulated amortization	(1,350)	0
Net	$ 450	$ 0