Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2021	Mar. 31, 2020
Numerator:
Net income (loss)	$ (225)	$ (364)	$ 7,421	$ 2,775	$ (589)	$ 10,196
Denominator:
Weighted average basic shares (in shares)	11,707		11,621		11,690	11,617
Dilutive effect of restricted stock units (in shares)	0		60		0	56
Weighted average diluted shares (in shares)	11,707		11,681		11,690	11,673
Earnings (loss) per share:
Basic (in dollars per share)	$ (0.02)		$ 0.64		$ (0.05)	$ 0.88
Diluted (in dollars per share)	$ (0.02)		$ 0.64		$ (0.05)	$ 0.87