Condensed Consolidated Statements of Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Common Stock	Treasury Stock	Accumulated Other Comprehensive Income	Accumulated Deficit	Total
Beginning balance (in shares) at Sep. 30, 2018	27,577
Common Stock, Number of Shares [Abstract]
Stock-based compensation (in shares)	91
Stock option exercises (in shares)	0
Ending balance (in shares) at Dec. 31, 2018	27,668
Balance, beginning of period at Sep. 30, 2018	$ 734,066		$ 885	$ (580,425)
Common Stock, Number of Shares [Abstract]
Stock-based compensation	425
Stock option exercises	0
Tax withholding paid on behalf of employees for stock-based awards	(150)
Translation adjustment			14		$ 14
Net loss				(5,538)	(5,538)
Balance, end of period at Dec. 31, 2018	$ 734,341	$ (47,721)	899	(585,963)	$ 101,556
Beginning balance (in shares) at Sep. 30, 2019	28,893				28,893
Common Stock, Number of Shares [Abstract]
Stock-based compensation (in shares)	55
Stock option exercises (in shares)	0
Ending balance (in shares) at Dec. 31, 2019	28,948				28,948
Balance, beginning of period at Sep. 30, 2019	$ 739,926		950	(616,409)
Common Stock, Number of Shares [Abstract]
Stock-based compensation	801
Stock option exercises	0
Tax withholding paid on behalf of employees for stock-based awards	(47)
Translation adjustment			(36)		$ (36)
Net loss				(1,335)	(1,335)
Balance, end of period at Dec. 31, 2019	$ 740,680	$ (47,721)	$ 914	$ (617,744)	$ 76,129