Business Information - Long-lived Assets by Geographic Areas (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	$ 52,654	$ 58,753
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	29,595	33,114
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	$ 23,059	$ 25,639