Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Net income (loss)	$ (21,957)	$ 4,498	$ (24,364)	$ 9,228
Weighted average shares - basic	27,110	26,977	27,100	26,971
Effect of dilutive securities (in shares)		81		39
Weighted average shares - diluted	27,110	27,058	27,100	27,010
Net income (loss) per share, basic (in dollars per share)	$ (0.81)	$ 0.17	$ (0.90)	$ 0.34
Net income (loss) per share, diluted (in dollars per share)	$ (0.81)	$ 0.17	$ (0.90)	$ 0.34
RSUs
Anti-dilutive employee share-based awards	1,000	0	1,000	0