Income Taxes Reconciliation of our valuation allowance on deferred tax assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Tax cuts and jobs act of 2017, change in tax rate, deferred tax liability, income tax (expense) benefit		$ 3,641
Valuation Allowance of Deferred Tax Assets
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation allowance beginning of period	$ 41,084	36,683	$ 48,573
Change in assessment	1,650	(865)	0
Current year operations	(19,856)	3,495	(1,435)
Foreign currency and other	3,012	2,254	71
Acquisitions / Dispositions	(2,592)	(483)	(10,526)
Valuation allowance end of period	$ 23,298	$ 41,084	$ 36,683