Calculation of Weighted Average Common Shares and Common Equivalent Shares Outstanding (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Mar. 31, 2014
Earnings Per Share [Abstract]
Net income (loss)	$ (5,182)	$ 10,816	$ (10,627)	$ 34,992
Less: Income allocable to unvested restricted stock		109		353
Income (loss) available to common shareholders	(5,182)	10,707	(10,627)	34,639
Reallocation of participating earnings				1
Income (loss) attributable to common shareholders for diluted earnings per share	$ (5,182)	$ 10,707	$ (10,627)	$ 34,640
Weighted average number of common share equivalents:
Common shares used in basic earnings (loss) per share	13,002,616	12,950,416	12,990,129	12,948,788
Common share equivalents outstanding related to stock options		51,967		52,287
Total weighted average common shares and common share equivalents used in diluted earnings (loss) per share	13,002,616	13,002,383	12,990,129	13,001,075
Basic	$ (0.40)	$ 0.83	$ (0.82)	$ 2.68
Diluted	$ (0.40)	$ 0.82	$ (0.82)	$ 2.66