Property, Plant and Equipment - Schedule (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020
Property, Plant and Equipment [Line Items]
Right-of-use Asset	$ 2,252	$ 2,540
Property, plant and equipment, at cost	262,674	208,796
Accumulated amortization	(131,955)	(120,061)
Property, plant and equipment, net	130,719	88,735
Buildings, land, and land use right
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	7,669	11,282
Computer equipment and software
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	71,067	67,418
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	93,140	74,690
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	5,003	4,978
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	31,108	29,899
Capital projects in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 52,435	$ 17,989