Long-lived Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019
Schedule Of Long Lived Assets [Line Items]
Long-lived assets, excluding deferred tax assets	$ 121,908	$ 130,558
United States
Schedule Of Long Lived Assets [Line Items]
Long-lived assets, excluding deferred tax assets	114,119	118,064
Canada
Schedule Of Long Lived Assets [Line Items]
Long-lived assets, excluding deferred tax assets	6,654	10,419
Colombia
Schedule Of Long Lived Assets [Line Items]
Long-lived assets, excluding deferred tax assets	1	671
Russian Federation
Schedule Of Long Lived Assets [Line Items]
Long-lived assets, excluding deferred tax assets	717	961
United Kingdom
Schedule Of Long Lived Assets [Line Items]
Long-lived assets, excluding deferred tax assets	404	430
China
Schedule Of Long Lived Assets [Line Items]
Long-lived assets, excluding deferred tax assets	$ 13	$ 13