CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 16,660	$ 9,890	$ (7,152)
Foreign currency translation adjustments	60	(2,743)	(3,100)
Postretirement benefit adjustment, net of tax	(26)	(25)	75
Comprehensive income (loss)	$ 16,694	$ 7,122	$ (10,177)