Income Taxes Reconciliation of our valuation allowance on deferred tax assets (Details) - Valuation Allowance of Deferred Tax Assets - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation allowance beginning of period	$ 23,298	$ 41,084	$ 36,683
Change in assessment	(6,140)	1,650	(865)
Current year operations	7,300	(19,856)	3,495
Foreign currency and other	(3,219)	3,012	2,254
Acquisitions / Dispositions	(60)	(2,592)	(483)
Valuation allowance end of period	$ 21,299	$ 23,298	$ 41,084