Business Information - Long-lived Assets by Geographic Areas (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Sep. 30, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	$ 58,753	$ 72,382
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	33,114	44,108
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	$ 25,639	$ 28,274