Goodwill and Other Identifiable Intangible Assets, Net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018		Sep. 30, 2018
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 121,399		$ 121,399			$ 122,910
Accumulated amortization	(88,608)		(88,608)			(83,590)
Net	32,791		32,791			39,320	[1]
Amortization expense			6,669	$ 6,866	[1]
Purchased and Core Technology
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	57,888		57,888			58,102
Accumulated amortization	(50,455)		(50,455)			(48,693)
Net	7,433		7,433			9,409
License Agreements
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	102		102			102
Accumulated amortization	(67)		(67)			(46)
Net	35		35			56
Patents and Trademarks
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	14,552		14,552			15,701
Accumulated amortization	(11,725)		(11,725)			(12,242)
Net	2,827		2,827			3,459
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	46,457		46,457			46,605
Accumulated amortization	(24,261)		(24,261)			(21,049)
Net	22,196		22,196			25,556
Non-compete Agreements
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	600		600			600
Accumulated amortization	(300)		(300)			(210)
Net	300		300			390
Order backlog
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,800		1,800			1,800
Accumulated amortization	(1,800)		(1,800)			(1,350)
Net	0		0			$ 450
Cost of Sales and General and Administrative Expense
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 2,100	$ 2,600	$ 6,700	$ 6,900

[1] Prior period information has been restated for the adoption of ASU No. 2014-09, “Revenue from Contracts with Customers (Topic 606),” which we adopted on October 1, 2018.