Long-lived Assets, Excluding Deferred Tax Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Schedule Of Long Lived Assets [Line Items]
Long-lived assets, excluding deferred tax assets	$ 122,180	$ 119,070
United States
Schedule Of Long Lived Assets [Line Items]
Long-lived assets, excluding deferred tax assets	106,079	108,021
Canada
Schedule Of Long Lived Assets [Line Items]
Long-lived assets, excluding deferred tax assets	13,515	7,325
Colombia
Schedule Of Long Lived Assets [Line Items]
Long-lived assets, excluding deferred tax assets	1,002	1,747
Russian Federation
Schedule Of Long Lived Assets [Line Items]
Long-lived assets, excluding deferred tax assets	1,143	1,461
United Kingdom
Schedule Of Long Lived Assets [Line Items]
Long-lived assets, excluding deferred tax assets	428	502
China
Schedule Of Long Lived Assets [Line Items]
Long-lived assets, excluding deferred tax assets	$ 13	$ 14