Fair Value Measurements - Foreign Exchange Contracts (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
Assets:
Foreign exchange contracts	$ 17	$ 170
Liabilities:
Foreign exchange contracts	340	177
Significant Other Observable Inputs (Level 2)
Assets:
Foreign exchange contracts	17	170
Liabilities:
Foreign exchange contracts	340	$ 177
Significant Other Observable Inputs (Level 2) | Maximum
Assets:
Foreign exchange contracts	$ 100