Income Taxes Components of Income Tax Expense (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Tax cuts and jobs act of 2017, change in tax rate, deferred tax liability, income tax (expense) benefit										$ 3,641
Current:
Federal									$ 0	0	$ 0
State									(591)	(400)	(911)
Foreign									(8,014)	(7,239)	(6,703)
Current income tax provision									(8,605)	(7,639)	(7,614)
Deferred:
Federal									115	(3,597)	6,311
State									401	196	(209)
Foreign									718	1,453	130
Deferred income tax provision									1,234	(1,948)	6,232
Income taxes	$ (4,035)	$ (740)	$ 7	$ (2,603)	$ (10,721)	$ (7,959)	$ 4,579	$ 4,514	$ (7,371)	$ (9,587)	$ (1,382)