Segment Information - Reconciliation of Reportable Segment Operating Income (Loss) to Corresponding Consolidated Amounts (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Segment Reporting Information [Line Items]
Amortization of acquired intangible assets			$ 17,700	$ 12,700
Restructuring Charges	$ 82	$ 828	131	2,663
Total operating income (loss)	26,679	18,770	71,338	46,732
Operating Segments
Segment Reporting Information [Line Items]
Total operating income (loss)	35,708	27,322	95,449	66,097
Segment Reconciling Items
Segment Reporting Information [Line Items]
Amortization of acquired intangible assets	5,080	3,278	14,298	9,636
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Other unallocated corporate expenses	$ 3,867	$ 4,446	$ 9,682	$ 7,066