Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Paid-in Capital	Accumulated Deficit
Beginning balance (in shares) at Sep. 30, 2018		33,522,000
Beginning balance at Sep. 30, 2018	$ 644,027	$ 34	$ 880,025	$ (236,032)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income and comprehensive income (loss)	7,311			7,311
Amortization of nonvested stock awards	2,114		2,114
Exercises of stock options (in shares)		1,000
Exercises of stock options	7		7
Shares issued under employee stock plans, net (in shares)		910,000
Forfeiture and other settlements of restricted stock (in shares)		(28,000)
Common stock redeemed for tax liability (in shares)		(176,000)
Common stock redeemed for tax liability	(1,850)		(1,850)
Share repurchases (in shares)		(1,554,000)
Share repurchases	(16,500)	$ (1)	(16,499)
Ending balance (in shares) at Dec. 31, 2018		32,675,000
Ending balance at Dec. 31, 2018	635,109	$ 33	863,797	(228,721)
Beginning balance (in shares) at Sep. 30, 2018		33,522,000
Beginning balance at Sep. 30, 2018	644,027	$ 34	880,025	(236,032)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share repurchases	(34,600)
Ending balance (in shares) at Sep. 30, 2019		30,933,000
Ending balance at Sep. 30, 2019	538,754	$ 31	854,275	(315,552)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income and comprehensive income (loss)	2,746			2,746
Amortization of nonvested stock awards	2,311		2,311
Exercises of stock options (in shares)		47,000
Exercises of stock options	173		173
Shares issued under employee stock plans, net (in shares)		574,000
Forfeiture and other settlements of restricted stock (in shares)		(1,000)
Forfeiture and other settlements of restricted stock	(2,058)		(2,058)
Common stock redeemed for tax liability (in shares)		(170,000)
Common stock redeemed for tax liability	$ (2,646)		(2,646)
Share repurchases (in shares)	0
Ending balance (in shares) at Dec. 31, 2019		31,383,000
Ending balance at Dec. 31, 2019	$ 539,280	$ 31	$ 852,055	$ (312,806)