Income Tax Expense - Total Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Income Tax Expense
Income tax expense (benefit) from continuing operations	$ 14,278	$ 20,388	$ (5,170)
Income tax expense from discontinued operations	23,501	789	1,060
Total income tax expense (benefit)	$ 37,779	$ 21,177	$ (4,110)