Restructuring and Other Costs, Net - Schedule of Accrual Activity Relating to Restructuring Reserves (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Restructuring Cost and Reserve [Line Items]
Balance at October 1, 2019			$ 4,391
Restructuring and other costs, net	$ 2,870	$ 4,329	10,424	$ 7,456
Cash payments			(10,386)
Foreign exchange impact on ending balance			(7)
Balance at March 31, 2020	4,422		4,422
Personnel
Restructuring Cost and Reserve [Line Items]
Balance at October 1, 2019			489
Restructuring and other costs, net	321	220	681	(443)
Cash payments			(657)
Foreign exchange impact on ending balance			(7)
Balance at March 31, 2020	506		506
Facilities
Restructuring Cost and Reserve [Line Items]
Balance at October 1, 2019			26
Restructuring and other costs, net		(381)		1,674
Cash payments			(10)
Balance at March 31, 2020	16		16
Spin-Off
Restructuring Cost and Reserve [Line Items]
Balance at October 1, 2019			3,876
Restructuring and other costs, net	2,549	$ 4,490	9,743	$ 6,225
Cash payments			(9,719)
Balance at March 31, 2020	$ 3,900		$ 3,900