Income Taxes - Reconciliation of Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Provision for income taxes attributable to continuing operations
Income tax expense (benefit) at the federal statutory rate	$ 15,134	$ 128	$ (23,172)
State taxes, net of federal benefit	(714)	2,476	(701)
Mexico inflation adjustment	(1,286)	(142)	(302)
Captive insurance company	0	0	(393)
Non-deductible items	1,114	1,860	449
Foreign tax credit	(321)	2,788	(2,413)
Foreign rate differential	(172)	277	880
Change in net operating loss carryforward	1,180	0	0
Change in valuation allowance	(3,211)	1,511	4,846
Stock compensation	(386)	0	0
Uncertain tax positions	472	0	1,781
Tax basis balance sheet adjustment	0	0	2,516
Other	(604)	463	2,484
Total income tax expense (benefit)	$ 11,206	$ 9,361	$ (14,025)
Effective tax rate	26.00%	2579.00%	21.00%