Long-lived Assets, Excluding Deferred Tax Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
Schedule Of Long Lived Assets [Line Items]
Long-lived assets, excluding deferred tax assets	$ 130,558	$ 122,180
United States
Schedule Of Long Lived Assets [Line Items]
Long-lived assets, excluding deferred tax assets	118,064	106,079
Canada
Schedule Of Long Lived Assets [Line Items]
Long-lived assets, excluding deferred tax assets	10,419	13,515
Colombia
Schedule Of Long Lived Assets [Line Items]
Long-lived assets, excluding deferred tax assets	671	1,002
Russian Federation
Schedule Of Long Lived Assets [Line Items]
Long-lived assets, excluding deferred tax assets	961	1,143
United Kingdom
Schedule Of Long Lived Assets [Line Items]
Long-lived assets, excluding deferred tax assets	430	428
China
Schedule Of Long Lived Assets [Line Items]
Long-lived assets, excluding deferred tax assets	$ 13	$ 13