Segment and Geographic Information - Long-Lived Assets, Consisting of Property, Plant and Equipment by Geographic Area (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Sep. 30, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment, net	$ 58,462	$ 54,885
North America
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment, net	52,235	49,505
UNITED STATES
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment, net	52,000	49,300
Asia/Pacific
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment, net	676	952
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment, net	$ 5,551	$ 4,428