Restructuring and Related Charges (Details) - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost	$ 5,012
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning of the period	3,542	$ 13,217
Restructuring charges related to VSP	320	15,431
Charges related to other initiatives	5,964	3,295
Write off charge and other non‑cash activity	(308)	(374)
Cash payments	(9,095)	(24,325)
Other adjustments	28	(159)
Restructuring reserve, end of the period	451	7,085
Cost of Product Sales and Services [Member]
Restructuring Reserve [Roll Forward]
Restructuring charges related to VSP	1,936	8,141
General and Administrative Expense [Member]
Restructuring Reserve [Roll Forward]
Restructuring charges related to VSP	3,113	4,874
Sales and Marketing Expense [Member]
Restructuring Reserve [Roll Forward]
Restructuring charges related to VSP	733	5,377
Research and Development Expense [Member]
Restructuring Reserve [Roll Forward]
Restructuring charges related to VSP	$ 503	$ 334