Restructuring and Other Costs, Net - Schedule of Restructuring and Other Costs, Net (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Restructuring Cost And Reserve [Line Items]
Restructuring and other costs, net	$ 537	$ 2,870	$ 1,017	$ 10,424
Personnel
Restructuring Cost And Reserve [Line Items]
Restructuring and other costs, net	45	321	381	681
Facilities
Restructuring Cost And Reserve [Line Items]
Restructuring and other costs, net	447		565
Restructuring Subtotal
Restructuring Cost And Reserve [Line Items]
Restructuring and other costs, net	492	321	946	681
Other
Restructuring Cost And Reserve [Line Items]
Restructuring and other costs, net	$ 45	$ 2,549	$ 71	$ 9,743