Income Taxes - Schedule of Valuation Allowance (Details) - Valuation Allowance of Deferred Tax Assets - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance	$ 8,767	$ 8,439	$ 10,056
Charged to cost and expenses	1,575	(260)	(1,934)
Charged to other accounts	(745)	588	317
Ending balance	$ 9,597	$ 8,767	$ 8,439