Segment Information - Reconciliation of Reportable Segment Operating Income (Loss) to Corresponding Consolidated Amounts (Details) - USD ($) $ in Thousands	3 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Amortization of acquired intangible assets	$ 7,800	$ 5,500
Restructuring Charges	59
Segment operating income (loss)	5,333	4,925
Operating Segments
Segment Reporting Information [Line Items]
Segment operating income (loss)	17,731	10,322
Segment Reconciling Items
Segment Reporting Information [Line Items]
Amortization of acquired intangible assets	5,768	4,588
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Other unallocated corporate expenses	$ 6,571	$ 809

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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