Business Information - Long-lived Assets by Geographic Areas (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	$ 46,641	$ 52,654
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	35,079	29,595
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	$ 11,562	$ 23,059