Goodwill and other Identifiable Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Sep. 30, 2016
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 86,308	$ 75,694
Accumulated amortization	(74,508)	(71,653)
Net	11,800	4,041
Purchased and Core Technology
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	51,292	46,594
Accumulated amortization	(46,304)	(44,999)
Net	4,988	1,595
License Agreements
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	18	18
Accumulated amortization	(17)	(10)
Net	1	8
Patents and Trademarks
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	12,484	11,619
Accumulated amortization	(11,280)	(10,871)
Net	1,204	748
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	21,914	17,463
Accumulated amortization	(16,817)	(15,773)
Net	5,097	1,690
Noncompete Agreements
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	600	0
Accumulated amortization	(90)	0
Net	$ 510	$ 0