Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Reconciliation of Unrecognized Tax Benefits
Unrecognized tax benefits – beginning of year	$ 2,055	$ 0	$ 0
Additions for tax positions taken in prior years	604	2,055	0
Additions for tax positions of the current year	0	0	0
Settlements with tax authorities/statute lapses	(830)	0	0
Unrecognized tax benefits – end of year	$ 1,829	$ 2,055	$ 0