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, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information [Line Items]
Amortization of acquired intangible assets	$ 4,300	$ 3,800	$ 12,700	$ 11,100
Restructuring charges	828	996	2,663	9,807
Total operating income (loss)	18,770	8,494	46,732	(6,165)
Operating Segments
Segment Reporting Information [Line Items]
Total operating income (loss)	27,322	12,383	66,097	15,162
Segment Reconciling Items
Segment Reporting Information [Line Items]
Amortization of acquired intangible assets	3,278	2,754	9,636	8,056
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Other unallocated corporate expenses	$ 4,446	$ 139	$ 7,066	$ 3,464